Greek letters are used in mathematics

Mathematics

Mathematics is the study of quantity, space, structure, and change. Mathematicians seek out patterns and formulate new conjectures. Mathematicians resolve the truth or falsity of conjectures by mathematical proofs, which are arguments sufficient to convince other mathematicians of their validity...

, science

Science

Science is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe...

, engineering

Engineering

Engineering is the discipline, art, skill and profession of acquiring and applying scientific, mathematical, economic, social, and practical knowledge, in order to design and build structures, machines, devices, systems, materials and processes that safely realize improvements to the lives of...

, and other areas where mathematical notation is used as symbols for constant

Mathematical constant

A mathematical constant is a special number, usually a real number, that is "significantly interesting in some way". Constants arise in many different areas of mathematics, with constants such as and occurring in such diverse contexts as geometry, number theory and calculus.What it means for a...

s, special functions, and also conventionally for variables

Variable (mathematics)

In mathematics, a variable is a value that may change within the scope of a given problem or set of operations. In contrast, a constant is a value that remains unchanged, though often unknown or undetermined. The concepts of constants and variables are fundamental to many areas of mathematics and...

 representing certain quantities. In these contexts, the capital letters and the small letters represent distinct and unrelated entities. Those Greek letters which have the same form as Latin letters are usually not used: capital A, B, E, H, I, K, M, N, O, P, T, X, Y, Z. Small ι (iota), ο (omicron) and υ (upsilon) are also rarely used, since they closely resemble the Latin letters i, o and u. Sometimes font variants of Greek letters are used as distinct symbols in mathematics, in particular for φ (phi) and π (pi).

In mathematical finance

Mathematical finance

Mathematical finance is a field of applied mathematics, concerned with financial markets. The subject has a close relationship with the discipline of financial economics, which is concerned with much of the underlying theory. Generally, mathematical finance will derive and extend the mathematical...

, the Greeks are the variables denoted by Greek letters used to describe the risk of certain investments.

English-speaking mathematicians use neither the modern nor the historical

Ancient Greek phonology

Ancient Greek phonology is the study of the phonology, or pronunciation, of Ancient Greek. Because of the passage of time, the original pronunciation of Ancient Greek, like that of all ancient languages, can never be known with absolute certainty...

 Greek pronunciations of the names of the letters, but the traditional English pronunciation

English pronunciation of Greek letters

This table gives the common English pronunciation of Greek letters using the International Phonetic Alphabet It is the pronunciation of the ancient Greek names of the Greek letters using the English teaching pronunciation...

, e.g. ˈθeɪtə for θ, cf. ancient tʰɛ̂ːta and modern ˈθita.

Typography

The Greek letter forms used in maths are often different from those used in Greek-language

Greek language

Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...

 text: they are designed to be used in isolation, not connected to other letters, and some use variant forms which are not normally used in current Greek typography.

The OpenType

OpenType

OpenType is a format for scalable computer fonts. It was built on its predecessor TrueType, retaining TrueType's basic structure and adding many intricate data structures for prescribing typographic behavior...

 font format has the feature tag 'mgrk' "Mathematical Greek" to identify a glyph

Glyph

A glyph is an element of writing: an individual mark on a written medium that contributes to the meaning of what is written. A glyph is made up of one or more graphemes....

 as representing a Greek letter to be used in mathematical (as opposed to Greek language) contexts.

The table below shows a comparison of Greek letters rendered in TeX

TeX

TeX is a typesetting system designed and mostly written by Donald Knuth and released in 1978. Within the typesetting system, its name is formatted as ....

 and HTML.
The font used in the TeX rendering is an italic style. This is in line with the convention that variables should be italicized. As Greek letters are more often than not used as variables in mathematical formulas, a Greek letter appearing similar to the TeX rendering is more likely to be encountered in works involving mathematics.

Greek letters
Name	TeX	HTML		Name	TeX	HTML		Name	TeX	HTML		Name	TeX	HTML		Name	TeX	HTML
Alpha		Αα		Digamma		Ϝϝ		Kappa		Κκ		Omicron		Οο		Upsilon		Υυ
Beta		Ββ		Zeta		Ζζ		Lambda		Λλ		Pi		Ππϖ		Phi		Φϕφ
Gamma		Γγ		Eta		Ηη		Mu		Μμ		Rho		Ρρϱ		Chi		Χχ
Delta		Δδ		Theta		Θθϑ		Nu		Νν		Sigma		Σσς		Psi		Ψψ
Epsilon		Εϵε		Iota		Ιι		Xi		Ξξ		Tau		Ττ		Omega		Ωω

Αα (alpha)

• α represents:
  • the first angle
    Angle
    In geometry, an angle is the figure formed by two rays sharing a common endpoint, called the vertex of the angle.Angles are usually presumed to be in a Euclidean plane with the circle taken for standard with regard to direction. In fact, an angle is frequently viewed as a measure of an circular arc...
    
     in a triangle
    Triangle
    A triangle is one of the basic shapes of geometry: a polygon with three corners or vertices and three sides or edges which are line segments. A triangle with vertices A, B, and C is denoted ....
    
    , opposite the side A
  • one root of a quadratic equation
    Quadratic equation
    In mathematics, a quadratic equation is a univariate polynomial equation of the second degree. A general quadratic equation can be written in the formax^2+bx+c=0,\,...
    
    , where β represents the other
  • the ratio of collector current to emitter current in a bipolar junction transistor
    Transistor
    A transistor is a semiconductor device used to amplify and switch electronic signals and power. It is composed of a semiconductor material with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor's terminals changes the current...
    
     (BJT) in electronics
  • the statistical significance
    Statistical significance
    In statistics, a result is called statistically significant if it is unlikely to have occurred by chance. The phrase test of significance was coined by Ronald Fisher....
    
     of a result
  • the false positive rate
    Type I and type II errors
    In statistical test theory the notion of statistical error is an integral part of hypothesis testing. The test requires an unambiguous statement of a null hypothesis, which usually corresponds to a default "state of nature", for example "this person is healthy", "this accused is not guilty" or...
    
     in statistics
  • the reciprocal
    Multiplicative inverse
    In mathematics, a multiplicative inverse or reciprocal for a number x, denoted by 1/x or x−1, is a number which when multiplied by x yields the multiplicative identity, 1. The multiplicative inverse of a fraction a/b is b/a. For the multiplicative inverse of a real number, divide 1 by the...
    
     of the sacrifice ratio
  • the fine structure constant in physics
  • the angle of attack
    Angle of attack
    Angle of attack is a term used in fluid dynamics to describe the angle between a reference line on a lifting body and the vector representing the relative motion between the lifting body and the fluid through which it is moving...
    
     of an airplane
  • an alpha particle
    Alpha particle
    Alpha particles consist of two protons and two neutrons bound together into a particle identical to a helium nucleus, which is classically produced in the process of alpha decay, but may be produced also in other ways and given the same name...
    
     (He²⁺)
  • angular acceleration
    Angular acceleration
    Angular acceleration is the rate of change of angular velocity over time. In SI units, it is measured in radians per second squared , and is usually denoted by the Greek letter alpha .- Mathematical definition :...
    
     in physics
  • the linear thermal expansion coefficient
  • the thermal diffusivity
    Thermal diffusivity
    In heat transfer analysis, thermal diffusivity is the thermal conductivity divided by density and specific heat capacity at constant pressure. It has the SI unit of m²/s...
    
    
  • the alpha carbon
    Alpha carbon
    The alpha carbon in organic chemistry refers to the first carbon that attaches to a functional group . By extension, the second carbon is the beta carbon, and so on....
    
     is the first carbon after the carbon that attaches to a functional group in organic chemistry
    Organic chemistry
    Organic chemistry is a subdiscipline within chemistry involving the scientific study of the structure, properties, composition, reactions, and preparation of carbon-based compounds, hydrocarbons, and their derivatives...
    
    
  • the α-carbon is the backbone carbon next to the carbonyl carbon in amino acids
  • right ascension
    Right ascension
    Right ascension is the astronomical term for one of the two coordinates of a point on the celestial sphere when using the equatorial coordinate system. The other coordinate is the declination.-Explanation:...
    
     in astrometry
    Astrometry
    Astrometry is the branch of astronomy that involves precise measurements of the positions and movements of stars and other celestial bodies. The information obtained by astrometric measurements provides information on the kinematics and physical origin of our Solar System and our Galaxy, the Milky...
    
    

Ββ (beta)

• Β represents the beta function
• β represents:
  • the second angle in a triangle
    Triangle
    A triangle is one of the basic shapes of geometry: a polygon with three corners or vertices and three sides or edges which are line segments. A triangle with vertices A, B, and C is denoted ....
    
    , opposite the side B
  • one root of a quadratic equation
    Quadratic equation
    In mathematics, a quadratic equation is a univariate polynomial equation of the second degree. A general quadratic equation can be written in the formax^2+bx+c=0,\,...
    
    , where α represents the other
  • the ratio of collector current to base current in a bipolar junction transistor
    Transistor
    A transistor is a semiconductor device used to amplify and switch electronic signals and power. It is composed of a semiconductor material with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor's terminals changes the current...
    
     (BJT) in electronics (current gain)
  • the false negative rate
    Type I and type II errors
    In statistical test theory the notion of statistical error is an integral part of hypothesis testing. The test requires an unambiguous statement of a null hypothesis, which usually corresponds to a default "state of nature", for example "this person is healthy", "this accused is not guilty" or...
    
     in statistics
  • the beta coefficient
    Beta coefficient
    In finance, the Beta of a stock or portfolio is a number describing the relation of its returns with those of the financial market as a whole.An asset has a Beta of zero if its returns change independently of changes in the market's returns...
    
    , the non-diversifiable risk, of an asset in mathematical finance
    Mathematical finance
    Mathematical finance is a field of applied mathematics, concerned with financial markets. The subject has a close relationship with the discipline of financial economics, which is concerned with much of the underlying theory. Generally, mathematical finance will derive and extend the mathematical...
    
    
  • the sideslip angle of an airplane
  • the first-order effects of variations in Coriolis force with latitude
    Latitude
    In geography, the latitude of a location on the Earth is the angular distance of that location south or north of the Equator. The latitude is an angle, and is usually measured in degrees . The equator has a latitude of 0°, the North pole has a latitude of 90° north , and the South pole has a...
    
     in planetary dynamics
  • a beta particle
    Beta particle
    Beta particles are high-energy, high-speed electrons or positrons emitted by certain types of radioactive nuclei such as potassium-40. The beta particles emitted are a form of ionizing radiation also known as beta rays. The production of beta particles is termed beta decay...
    
     (e^-)
  • sound intensity
    Sound intensity
    Sound intensity or acoustic intensity is defined as the sound power Pac per unit area A. The usual context is the noise measurement of sound intensity in the air at a listener's location.-Acoustic intensity:...
    
    
  • velocity divided by the speed of light in special relativity
    Special relativity
    Special relativity is the physical theory of measurement in an inertial frame of reference proposed in 1905 by Albert Einstein in the paper "On the Electrodynamics of Moving Bodies".It generalizes Galileo's...
    
    
  • the beta brain wave in brain
    Brain
    The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...
    
     or cognitive sciences
  • ecliptic latitude in astrometry
    Astrometry
    Astrometry is the branch of astronomy that involves precise measurements of the positions and movements of stars and other celestial bodies. The information obtained by astrometric measurements provides information on the kinematics and physical origin of our Solar System and our Galaxy, the Milky...
    
    

Γγ (gamma)

• Γ represents:
  • the reflection coefficient
    Reflection coefficient
    The reflection coefficient is used in physics and electrical engineering when wave propagation in a medium containing discontinuities is considered. A reflection coefficient describes either the amplitude or the intensity of a reflected wave relative to an incident wave...
    
     of a transmission or telecommunication line.
  • the confinement factor of an optical mode in a waveguide
    Waveguide
    A waveguide is a structure which guides waves, such as electromagnetic waves or sound waves. There are different types of waveguides for each type of wave...
    
    
  • the gamma function
    Gamma function
    In mathematics, the gamma function is an extension of the factorial function, with its argument shifted down by 1, to real and complex numbers...
    
    , a generalization of the factorial
    Factorial
    In mathematics, the factorial of a non-negative integer n, denoted by n!, is the product of all positive integers less than or equal to n...
    
    
  • the upper incomplete gamma function
    Incomplete gamma function
    In mathematics, the gamma function is defined by a definite integral. The incomplete gamma function is defined as an integral function of the same integrand. There are two varieties of the incomplete gamma function: the upper incomplete gamma function is for the case that the lower limit of...
    
    
  • the modular group
    Modular group
    In mathematics, the modular group Γ is a fundamental object of study in number theory, geometry, algebra, and many other areas of advanced mathematics...
    
    , the group of fractional linear transformations
  • the gamma distribution, a continuous probability distribution defined using the gamma function
    Gamma function
    In mathematics, the gamma function is an extension of the factorial function, with its argument shifted down by 1, to real and complex numbers...
    
    
  • second-order sensitivity to price in mathematical finance
    Mathematical finance
    Mathematical finance is a field of applied mathematics, concerned with financial markets. The subject has a close relationship with the discipline of financial economics, which is concerned with much of the underlying theory. Generally, mathematical finance will derive and extend the mathematical...
    
    
  • the Christoffel symbols
    Christoffel symbols
    In mathematics and physics, the Christoffel symbols, named for Elwin Bruno Christoffel , are numerical arrays of real numbers that describe, in coordinates, the effects of parallel transport in curved surfaces and, more generally, manifolds. As such, they are coordinate-space expressions for the...
    
     of the second kind
• γ represents:
  • the partial safety factors applied to loads and materials in structural engineering
    Structural engineering
    Structural engineering is a field of engineering dealing with the analysis and design of structures that support or resist loads. Structural engineering is usually considered a specialty within civil engineering, but it can also be studied in its own right....
    
    
  • the specific weight
    Specific weight
    The specific weight is the weight per unit volume of a material. The symbol of specific weight is γ ....
    
     of substances
  • the lower incomplete gamma function
    Incomplete gamma function
    In mathematics, the gamma function is defined by a definite integral. The incomplete gamma function is defined as an integral function of the same integrand. There are two varieties of the incomplete gamma function: the upper incomplete gamma function is for the case that the lower limit of...
    
    
  • the third angle in a triangle
    Triangle
    A triangle is one of the basic shapes of geometry: a polygon with three corners or vertices and three sides or edges which are line segments. A triangle with vertices A, B, and C is denoted ....
    
    , opposite the side C
  • the Euler-Mascheroni constant
    Euler-Mascheroni constant
    The Euler–Mascheroni constant is a mathematical constant recurring in analysis and number theory, usually denoted by the lowercase Greek letter ....
    
     in mathematics
  • gamma ray
    Gamma ray
    Gamma radiation, also known as gamma rays or hyphenated as gamma-rays and denoted as γ, is electromagnetic radiation of high frequency . Gamma rays are usually naturally produced on Earth by decay of high energy states in atomic nuclei...
    
    s and the photon
    Photon
    In physics, a photon is an elementary particle, the quantum of the electromagnetic interaction and the basic unit of light and all other forms of electromagnetic radiation. It is also the force carrier for the electromagnetic force...
    
    
  • the heat capacity ratio
    Heat capacity ratio
    The heat capacity ratio or adiabatic index or ratio of specific heats, is the ratio of the heat capacity at constant pressure to heat capacity at constant volume . It is sometimes also known as the isentropic expansion factor and is denoted by \gamma or \kappa . The latter symbol kappa is...
    
     in thermodynamics
    Thermodynamics
    Thermodynamics is a physical science that studies the effects on material bodies, and on radiation in regions of space, of transfer of heat and of work done on or by the bodies or radiation...
    
    
  • the Lorentz factor
    Lorentz factor
    The Lorentz factor or Lorentz term appears in several equations in special relativity, including time dilation, length contraction, and the relativistic mass formula. Because of its ubiquity, physicists generally represent it with the shorthand symbol γ . It gets its name from its earlier...
    
     in special relativity
  • the damping constant (kg/s)

Δδ (delta)

• Δ represents:
  • a finite difference
    Finite difference
    A finite difference is a mathematical expression of the form f − f. If a finite difference is divided by b − a, one gets a difference quotient...
    
    
  • a difference operator
  • a symmetric difference
    Symmetric difference
    In mathematics, the symmetric difference of two sets is the set of elements which are in either of the sets and not in their intersection. The symmetric difference of the sets A and B is commonly denoted by A\,\Delta\,B\,orA \ominus B....
    
    
  • the Laplace operator
    Laplace operator
    In mathematics the Laplace operator or Laplacian is a differential operator given by the divergence of the gradient of a function on Euclidean space. It is usually denoted by the symbols ∇·∇, ∇2 or Δ...
    
    
  • the angle that subtends the arc of a circular curve in surveying
    Surveying
    See Also: Public Land Survey SystemSurveying or land surveying is the technique, profession, and science of accurately determining the terrestrial or three-dimensional position of points and the distances and angles between them...
    
    
  • the determinant
    Determinant
    In linear algebra, the determinant is a value associated with a square matrix. It can be computed from the entries of the matrix by a specific arithmetic expression, while other ways to determine its value exist as well...
    
     of an inverse matrix
    Matrix (mathematics)
    In mathematics, a matrix is a rectangular array of numbers, symbols, or expressions. The individual items in a matrix are called its elements or entries. An example of a matrix with six elements isMatrices of the same size can be added or subtracted element by element...
    
    
  • the maximum degree
    Degree (graph theory)
    In graph theory, the degree of a vertex of a graph is the number of edges incident to the vertex, with loops counted twice. The degree of a vertex v is denoted \deg. The maximum degree of a graph G, denoted by Δ, and the minimum degree of a graph, denoted by δ, are the maximum and minimum degree...
    
     of any vertex in a given graph
    Graph (mathematics)
    In mathematics, a graph is an abstract representation of a set of objects where some pairs of the objects are connected by links. The interconnected objects are represented by mathematical abstractions called vertices, and the links that connect some pairs of vertices are called edges...
    
    
  • the difference or change in a given variable, e.g. ∆v means a difference or change in velocity
    Velocity
    In physics, velocity is speed in a given direction. Speed describes only how fast an object is moving, whereas velocity gives both the speed and direction of the object's motion. To have a constant velocity, an object must have a constant speed and motion in a constant direction. Constant ...
    
    
  • sensitivity to price
    Greeks (finance)
    In mathematical finance, the Greeks are the quantities representing the sensitivities of the price of derivatives such as options to a change in underlying parameters on which the value of an instrument or portfolio of financial instruments is dependent. The name is used because the most common of...
    
     in mathematical finance
    Mathematical finance
    Mathematical finance is a field of applied mathematics, concerned with financial markets. The subject has a close relationship with the discipline of financial economics, which is concerned with much of the underlying theory. Generally, mathematical finance will derive and extend the mathematical...
    
    
  • distance to Earth, measured in astronomical unit
    Astronomical unit
    An astronomical unit is a unit of length equal to about or approximately the mean Earth–Sun distance....
    
    s
  • heat
    Heat
    In physics and thermodynamics, heat is energy transferred from one body, region, or thermodynamic system to another due to thermal contact or thermal radiation when the systems are at different temperatures. It is often described as one of the fundamental processes of energy transfer between...
    
     in a chemical formula
  • the discriminant in the quadratic formula which determines the nature of the roots
  • the degrees of freedom
    Degrees of freedom
    Degrees of freedom can mean:* Degrees of freedom , independent displacements and/or rotations that specify the orientation of the body or system...
    
     in a non-pooled statistical hypothesis test of two population means
• δ represents:
  • a variation in the calculus of variations
    Calculus of variations
    Calculus of variations is a field of mathematics that deals with extremizing functionals, as opposed to ordinary calculus which deals with functions. A functional is usually a mapping from a set of functions to the real numbers. Functionals are often formed as definite integrals involving unknown...
    
    
  • the Kronecker delta function
  • the force of interest
    Compound interest
    Compound interest arises when interest is added to the principal, so that from that moment on, the interest that has been added also itself earns interest. This addition of interest to the principal is called compounding...
    
     in mathematical finance
    Mathematical finance
    Mathematical finance is a field of applied mathematics, concerned with financial markets. The subject has a close relationship with the discipline of financial economics, which is concerned with much of the underlying theory. Generally, mathematical finance will derive and extend the mathematical...
    
    
  • the Dirac delta function
    Dirac delta function
    The Dirac delta function, or δ function, is a generalized function depending on a real parameter such that it is zero for all values of the parameter except when the parameter is zero, and its integral over the parameter from −∞ to ∞ is equal to one. It was introduced by theoretical...
    
    
  • the Skorokhod integral
    Skorokhod integral
    In mathematics, the Skorokhod integral, often denoted δ, is an operator of great importance in the theory of stochastic processes. It is named after the Ukrainian mathematician Anatoliy Skorokhod...
    
     in Malliavin calculus
    Malliavin calculus
    The Malliavin calculus, named after Paul Malliavin, is a theory of variational stochastic calculus. In other words it provides the mechanics to compute derivatives of random variables....
    
    , a subfield of stochastic analysis
  • the minimum degree
    Degree (graph theory)
    In graph theory, the degree of a vertex of a graph is the number of edges incident to the vertex, with loops counted twice. The degree of a vertex v is denoted \deg. The maximum degree of a graph G, denoted by Δ, and the minimum degree of a graph, denoted by δ, are the maximum and minimum degree...
    
     of any vertex in a given graph
    Graph (mathematics)
    In mathematics, a graph is an abstract representation of a set of objects where some pairs of the objects are connected by links. The interconnected objects are represented by mathematical abstractions called vertices, and the links that connect some pairs of vertices are called edges...
    
    
  • a partial charge. δ- represents a negative partial charge, and δ+ represents a positive partial charge chemistry
    Chemistry
    Chemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties. Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds....
    
     (See also: Solvation
    Solvation
    Solvation, also sometimes called dissolution, is the process of attraction and association of molecules of a solvent with molecules or ions of a solute...
    
    )
  • declination
    Declination
    In astronomy, declination is one of the two coordinates of the equatorial coordinate system, the other being either right ascension or hour angle. Declination in astronomy is comparable to geographic latitude, but projected onto the celestial sphere. Declination is measured in degrees north and...
    
     in astrometry
    Astrometry
    Astrometry is the branch of astronomy that involves precise measurements of the positions and movements of stars and other celestial bodies. The information obtained by astrometric measurements provides information on the kinematics and physical origin of our Solar System and our Galaxy, the Milky...
    
    
  • the Turner Function in computational material science
  • noncentrality measure in statistics
    Statistics
    Statistics is the study of the collection, organization, analysis, and interpretation of data. It deals with all aspects of this, including the planning of data collection in terms of the design of surveys and experiments....
    
    

Εε (epsilon)

• ε represents:
  • a small positive quantity; see limit
    Limit (mathematics)
    In mathematics, the concept of a "limit" is used to describe the value that a function or sequence "approaches" as the input or index approaches some value. The concept of limit allows mathematicians to define a new point from a Cauchy sequence of previously defined points within a complete metric...
    
    
  • a random error in regression analysis
    Regression analysis
    In statistics, regression analysis includes many techniques for modeling and analyzing several variables, when the focus is on the relationship between a dependent variable and one or more independent variables...
    
    
  • in set theory
    Set theory
    Set theory is the branch of mathematics that studies sets, which are collections of objects. Although any type of object can be collected into a set, set theory is applied most often to objects that are relevant to mathematics...
    
    , the limit ordinal
    Ordinal number
    In set theory, an ordinal number, or just ordinal, is the order type of a well-ordered set. They are usually identified with hereditarily transitive sets. Ordinals are an extension of the natural numbers different from integers and from cardinals...
    
     of the sequence
  • in computer science
    Computer science
    Computer science or computing science is the study of the theoretical foundations of information and computation and of practical techniques for their implementation and application in computer systems...
    
    , the empty string
    String (computer science)
    In formal languages, which are used in mathematical logic and theoretical computer science, a string is a finite sequence of symbols that are chosen from a set or alphabet....
    
    
  • the Levi-Civita symbol
    Levi-Civita symbol
    The Levi-Civita symbol, also called the permutation symbol, antisymmetric symbol, or alternating symbol, is a mathematical symbol used in particular in tensor calculus...
    
    
  • in electromagnetics, dielectric
    Dielectric
    A dielectric is an electrical insulator that can be polarized by an applied electric field. When a dielectric is placed in an electric field, electric charges do not flow through the material, as in a conductor, but only slightly shift from their average equilibrium positions causing dielectric...
    
     permittivity
    Permittivity
    In electromagnetism, absolute permittivity is the measure of the resistance that is encountered when forming an electric field in a medium. In other words, permittivity is a measure of how an electric field affects, and is affected by, a dielectric medium. The permittivity of a medium describes how...
    
    
  • emissivity
    Emissivity
    The emissivity of a material is the relative ability of its surface to emit energy by radiation. It is the ratio of energy radiated by a particular material to energy radiated by a black body at the same temperature...
    
    
  • strain
    Deformation (mechanics)
    Deformation in continuum mechanics is the transformation of a body from a reference configuration to a current configuration. A configuration is a set containing the positions of all particles of the body...
    
     in continuum mechanics
    Continuum mechanics
    Continuum mechanics is a branch of mechanics that deals with the analysis of the kinematics and the mechanical behavior of materials modelled as a continuous mass rather than as discrete particles...
    
    
  • permittivity
    Permittivity
    In electromagnetism, absolute permittivity is the measure of the resistance that is encountered when forming an electric field in a medium. In other words, permittivity is a measure of how an electric field affects, and is affected by, a dielectric medium. The permittivity of a medium describes how...
    
    
  • the Earth's axial tilt
    Axial tilt
    In astronomy, axial tilt is the angle between an object's rotational axis, and a line perpendicular to its orbital plane...
    
     in astrometry
    Astrometry
    Astrometry is the branch of astronomy that involves precise measurements of the positions and movements of stars and other celestial bodies. The information obtained by astrometric measurements provides information on the kinematics and physical origin of our Solar System and our Galaxy, the Milky...
    
    
  • elasticity
    Elasticity (economics)
    In economics, elasticity is the measurement of how changing one economic variable affects others. For example:* "If I lower the price of my product, how much more will I sell?"* "If I raise the price, how much less will I sell?"...
    
     in economics
    Economics
    Economics is the social science that analyzes the production, distribution, and consumption of goods and services. The term economics comes from the Ancient Greek from + , hence "rules of the house"...
    
    
  • expected value
    Expected value
    In probability theory, the expected value of a random variable is the weighted average of all possible values that this random variable can take on...
    
     in probability theory
    Probability theory
    Probability theory is the branch of mathematics concerned with analysis of random phenomena. The central objects of probability theory are random variables, stochastic processes, and events: mathematical abstractions of non-deterministic events or measured quantities that may either be single...
    
     and statistics
    Statistics
    Statistics is the study of the collection, organization, analysis, and interpretation of data. It deals with all aspects of this, including the planning of data collection in terms of the design of surveys and experiments....
    
    
  • electromotive force
    Electromotive force
    In physics, electromotive force, emf , or electromotance refers to voltage generated by a battery or by the magnetic force according to Faraday's Law, which states that a time varying magnetic field will induce an electric current.It is important to note that the electromotive "force" is not a...
    
    
• set membership symbol ∈ is based on ε

(digamma)

is sometimes used to represent the digamma function, though the Latin letter F (which is nearly identical) is usually substituted.

Ζζ (zeta)

• ζ represents:
  • the Riemann zeta function and other zeta functions in mathematics
    Mathematics
    Mathematics is the study of quantity, space, structure, and change. Mathematicians seek out patterns and formulate new conjectures. Mathematicians resolve the truth or falsity of conjectures by mathematical proofs, which are arguments sufficient to convince other mathematicians of their validity...
    
    
  • the coefficient of viscous friction
    Viscosity
    Viscosity is a measure of the resistance of a fluid which is being deformed by either shear or tensile stress. In everyday terms , viscosity is "thickness" or "internal friction". Thus, water is "thin", having a lower viscosity, while honey is "thick", having a higher viscosity...
    
     in polymer
    Polymer
    A polymer is a large molecule composed of repeating structural units. These subunits are typically connected by covalent chemical bonds...
    
     dynamics
  • the damping ratio
    Damping ratio
    [[Image:Damped spring.gif|right|frame|Underdamped [[spring–mass system]] with ζ 1 , and is referred to as overdamped.*Underdamped:If s is a complex number, then the solution is a decaying exponential combined with an oscillatory portion that looks like \exp...
    
    
  • relative vertical vorticity in fluid dynamics

Ηη (eta)

• η represents:
  • the intrinsic impedance of medium (usually free space)
  • the partial regression
    Regression analysis
    In statistics, regression analysis includes many techniques for modeling and analyzing several variables, when the focus is on the relationship between a dependent variable and one or more independent variables...
    
     coefficient
    Correlation ratio
    In statistics, the correlation ratio is a measure of the relationship between the statistical dispersion within individual categories and the dispersion across the whole population or sample. The measure is defined as the ratio of two standard deviations representing these types of variation...
    
     in statistics
  • elasticities
    Elasticity (economics)
    In economics, elasticity is the measurement of how changing one economic variable affects others. For example:* "If I lower the price of my product, how much more will I sell?"* "If I raise the price, how much less will I sell?"...
    
     in economics
  • the absolute vertical vorticity (relative vertical vorticity + Coriolis effect
    Coriolis effect
    In physics, the Coriolis effect is a deflection of moving objects when they are viewed in a rotating reference frame. In a reference frame with clockwise rotation, the deflection is to the left of the motion of the object; in one with counter-clockwise rotation, the deflection is to the right...
    
    ) in fluid dynamics
  • an index of refraction
  • a type of meson
    Meson
    In particle physics, mesons are subatomic particles composed of one quark and one antiquark, bound together by the strong interaction. Because mesons are composed of sub-particles, they have a physical size, with a radius roughly one femtometer: 10−15 m, which is about the size of a proton...
    
    
  • viscosity
    Viscosity
    Viscosity is a measure of the resistance of a fluid which is being deformed by either shear or tensile stress. In everyday terms , viscosity is "thickness" or "internal friction". Thus, water is "thin", having a lower viscosity, while honey is "thick", having a higher viscosity...
    
    
  • efficiency
    Efficiency (statistics)
    In statistics, an efficient estimator is an estimator that estimates the quantity of interest in some “best possible” manner. The notion of “best possible” relies upon the choice of a particular loss function — the function which quantifies the relative degree of undesirability of estimation errors...
    
    
  • the Minkowski metric tensor in relativity
  • noise in communication system models

Θθ (theta)

• Θ represents:
  • an asymptotically tight bound related to big O notation
    Big O notation
    In mathematics, big O notation is used to describe the limiting behavior of a function when the argument tends towards a particular value or infinity, usually in terms of simpler functions. It is a member of a larger family of notations that is called Landau notation, Bachmann-Landau notation, or...
    
    .
  • sensitivity to the passage of time in mathematical finance
    Mathematical finance
    Mathematical finance is a field of applied mathematics, concerned with financial markets. The subject has a close relationship with the discipline of financial economics, which is concerned with much of the underlying theory. Generally, mathematical finance will derive and extend the mathematical...
    
    
  • Θ (set theory), a certain ordinal number
    Ordinal number
    In set theory, an ordinal number, or just ordinal, is the order type of a well-ordered set. They are usually identified with hereditarily transitive sets. Ordinals are an extension of the natural numbers different from integers and from cardinals...
    
    
• θ represents:
  • a plane angle
    Angle
    In geometry, an angle is the figure formed by two rays sharing a common endpoint, called the vertex of the angle.Angles are usually presumed to be in a Euclidean plane with the circle taken for standard with regard to direction. In fact, an angle is frequently viewed as a measure of an circular arc...
    
     in geometry
    Geometry
    Geometry arose as the field of knowledge dealing with spatial relationships. Geometry was one of the two fields of pre-modern mathematics, the other being the study of numbers ....
    
    
  • the angle
    Angle
    In geometry, an angle is the figure formed by two rays sharing a common endpoint, called the vertex of the angle.Angles are usually presumed to be in a Euclidean plane with the circle taken for standard with regard to direction. In fact, an angle is frequently viewed as a measure of an circular arc...
    
     to the x axis in the xy-plane
    Plane (mathematics)
    In mathematics, a plane is a flat, two-dimensional surface. A plane is the two dimensional analogue of a point , a line and a space...
    
     in spherical or cylindrical coordinates
  • potential temperature in thermodynamics
  • the mean time between failure
    Mean time between failure
    Mean time between failures is the predicted elapsed time between inherent failures of a system during operation. MTBF can be calculated as the arithmetic mean time between failures of a system. The MTBF is typically part of a model that assumes the failed system is immediately repaired , as a...
    
     in reliability engineering
    Reliability engineering
    Reliability engineering is an engineering field, that deals with the study, evaluation, and life-cycle management of reliability: the ability of a system or component to perform its required functions under stated conditions for a specified period of time. It is often measured as a probability of...
    
    
  • soil water contents in soil science
  • Debye temperature
  • theta functions
• sometimes also ϑ ("script theta"), cursive form of theta, often used in handwriting
  • the first Chebyshev function
    Chebyshev function
    [Image:ChebyshevPsi.png|thumb|right|The Chebyshev function ψ, with x [Image:ChebyshevPsi.png|thumb|right|The Chebyshev function ψ, with x ...
    
     in number theory
    Number theory
    Number theory is a branch of pure mathematics devoted primarily to the study of the integers. Number theorists study prime numbers as well...
    
    

Ιι (iota)

• ι represents:
  • the index generator function in APL (in the form ⍳)

Κκ (kappa)

• κ represents:
  • the Von Kármán constant
    Von Kármán constant
    In fluid dynamics, the Von Kármán constant , named for Theodore von Kármán, is a dimensionless constant describing the logarithmic velocity profile of a turbulent fluid flow near a boundary with a no-slip condition...
    
    
  • the kappa curve
    Kappa curve
    In geometry, the kappa curve or Gutschoven's curve is a two-dimensional algebraic curve resembling the Greek letter κ .Using the Cartesian coordinate system it can be expressed as:x^2=a^2y^2or, using parametric equations:...
    
    
  • the condition number
    Condition number
    In the field of numerical analysis, the condition number of a function with respect to an argument measures the asymptotically worst case of how much the function can change in proportion to small changes in the argument...
    
     of a matrix
    Matrix (mathematics)
    In mathematics, a matrix is a rectangular array of numbers, symbols, or expressions. The individual items in a matrix are called its elements or entries. An example of a matrix with six elements isMatrices of the same size can be added or subtracted element by element...
    
     in numerical analysis
    Numerical analysis
    Numerical analysis is the study of algorithms that use numerical approximation for the problems of mathematical analysis ....
    
    
  • the connectivity
    Connectivity (graph theory)
    In mathematics and computer science, connectivity is one of the basic concepts of graph theory: it asks for the minimum number of elements which need to be removed to disconnect the remaining nodes from each other. It is closely related to the theory of network flow problems...
    
     of a graph
    Graph (mathematics)
    In mathematics, a graph is an abstract representation of a set of objects where some pairs of the objects are connected by links. The interconnected objects are represented by mathematical abstractions called vertices, and the links that connect some pairs of vertices are called edges...
    
     in graph theory
    Graph theory
    In mathematics and computer science, graph theory is the study of graphs, mathematical structures used to model pairwise relations between objects from a certain collection. A "graph" in this context refers to a collection of vertices or 'nodes' and a collection of edges that connect pairs of...
    
    
  • curvature
    Curvature
    In mathematics, curvature refers to any of a number of loosely related concepts in different areas of geometry. Intuitively, curvature is the amount by which a geometric object deviates from being flat, or straight in the case of a line, but this is defined in different ways depending on the context...
    
    
  • dielectric constant
    Dielectric constant
    The relative permittivity of a material under given conditions reflects the extent to which it concentrates electrostatic lines of flux. In technical terms, it is the ratio of the amount of electrical energy stored in a material by an applied voltage, relative to that stored in a vacuum...
    
     
  • thermal conductivity
    Thermal conductivity
    In physics, thermal conductivity, k, is the property of a material's ability to conduct heat. It appears primarily in Fourier's Law for heat conduction....
    
     (usually a lowercase Latin k)
  • thermal diffusivity
    Thermal diffusivity
    In heat transfer analysis, thermal diffusivity is the thermal conductivity divided by density and specific heat capacity at constant pressure. It has the SI unit of m²/s...
    
    
  • a spring constant (usually a lowercase Latin k)
  • the heat capacity ratio
    Heat capacity ratio
    The heat capacity ratio or adiabatic index or ratio of specific heats, is the ratio of the heat capacity at constant pressure to heat capacity at constant volume . It is sometimes also known as the isentropic expansion factor and is denoted by \gamma or \kappa . The latter symbol kappa is...
    
     in thermodynamics (usually γ)

Λλ (lambda)

• Λ represents:
  • the von Mangoldt function
    Von Mangoldt function
    In mathematics, the von Mangoldt function is an arithmetic function named after German mathematician Hans von Mangoldt.-Definition:The von Mangoldt function, conventionally written as Λ, is defined as...
    
     in number theory
    Number theory
    Number theory is a branch of pure mathematics devoted primarily to the study of the integers. Number theorists study prime numbers as well...
    
    
  • the set of logical axioms in the axiomatic method of logical deduction in first-order logic
    First-order logic
    First-order logic is a formal logical system used in mathematics, philosophy, linguistics, and computer science. It goes by many names, including: first-order predicate calculus, the lower predicate calculus, quantification theory, and predicate logic...
    
    
  • the cosmological constant
    Cosmological constant
    In physical cosmology, the cosmological constant was proposed by Albert Einstein as a modification of his original theory of general relativity to achieve a stationary universe...
    
    
  • a type of baryon
    Baryon
    A baryon is a composite particle made up of three quarks . Baryons and mesons belong to the hadron family, which are the quark-based particles...
    
    
  • a diagonal matrix of eigenvalues in linear algebra
    Linear algebra
    Linear algebra is a branch of mathematics that studies vector spaces, also called linear spaces, along with linear functions that input one vector and output another. Such functions are called linear maps and can be represented by matrices if a basis is given. Thus matrix theory is often...
    
    
  • the permeance of a material in electromagnetism
    Electromagnetism
    Electromagnetism is one of the four fundamental interactions in nature. The other three are the strong interaction, the weak interaction and gravitation...
    
    
• λ represents:
  • one wavelength
    Wavelength
    In physics, the wavelength of a sinusoidal wave is the spatial period of the wave—the distance over which the wave's shape repeats.It is usually determined by considering the distance between consecutive corresponding points of the same phase, such as crests, troughs, or zero crossings, and is a...
    
     of electromagnetic radiation
  • the decay constant in radioactivity
  • function expressions in the lambda calculus
    Lambda calculus
    In mathematical logic and computer science, lambda calculus, also written as λ-calculus, is a formal system for function definition, function application and recursion. The portion of lambda calculus relevant to computation is now called the untyped lambda calculus...
    
    
  • a general eigenvalue in linear algebra
    Linear algebra
    Linear algebra is a branch of mathematics that studies vector spaces, also called linear spaces, along with linear functions that input one vector and output another. Such functions are called linear maps and can be represented by matrices if a basis is given. Thus matrix theory is often...
    
    
  • the expected number of occurrences in a Poisson distribution
    Poisson distribution
    In probability theory and statistics, the Poisson distribution is a discrete probability distribution that expresses the probability of a given number of events occurring in a fixed interval of time and/or space if these events occur with a known average rate and independently of the time since...
    
     in probability
  • the arrival rate in queueing theory
    Queueing theory
    Queueing theory is the mathematical study of waiting lines, or queues. The theory enables mathematical analysis of several related processes, including arriving at the queue, waiting in the queue , and being served at the front of the queue...
    
    
  • the average lifetime or rate parameter in an exponential distribution
    Exponential distribution
    In probability theory and statistics, the exponential distribution is a family of continuous probability distributions. It describes the time between events in a Poisson process, i.e...
    
     (commonly used across statistics
    Statistics
    Statistics is the study of the collection, organization, analysis, and interpretation of data. It deals with all aspects of this, including the planning of data collection in terms of the design of surveys and experiments....
    
    , physics
    Physics
    Physics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...
    
    , and engineering
    Engineering
    Engineering is the discipline, art, skill and profession of acquiring and applying scientific, mathematical, economic, social, and practical knowledge, in order to design and build structures, machines, devices, systems, materials and processes that safely realize improvements to the lives of...
    
    )
  • the failure rate
    Failure rate
    Failure rate is the frequency with which an engineered system or component fails, expressed for example in failures per hour. It is often denoted by the Greek letter λ and is important in reliability engineering....
    
     in reliability engineering
    Reliability engineering
    Reliability engineering is an engineering field, that deals with the study, evaluation, and life-cycle management of reliability: the ability of a system or component to perform its required functions under stated conditions for a specified period of time. It is often measured as a probability of...
    
    
  • the mean
    Mean
    In statistics, mean has two related meanings:* the arithmetic mean .* the expected value of a random variable, which is also called the population mean....
    
     or average value (probability and statistics)
  • the latent heat of fusion
  • the lagrange multiplier in the mathematical optimization method, known as the shadow price
    Shadow price
    In constrained optimization in economics, the shadow price is the instantaneous change per unit of the constraint in the objective value of the optimal solution of an optimization problem obtained by relaxing the constraint...
    
     in economics
  • the Lebesgue measure
    Lebesgue measure
    In measure theory, the Lebesgue measure, named after French mathematician Henri Lebesgue, is the standard way of assigning a measure to subsets of n-dimensional Euclidean space. For n = 1, 2, or 3, it coincides with the standard measure of length, area, or volume. In general, it is also called...
    
     denotes the volume or measure of a Lebesgue measurable set
  • longitude
    Longitude
    Longitude is a geographic coordinate that specifies the east-west position of a point on the Earth's surface. It is an angular measurement, usually expressed in degrees, minutes and seconds, and denoted by the Greek letter lambda ....
    
     in geodesy
    Geodesy
    Geodesy , also named geodetics, a branch of earth sciences, is the scientific discipline that deals with the measurement and representation of the Earth, including its gravitational field, in a three-dimensional time-varying space. Geodesists also study geodynamical phenomena such as crustal...
    
    
  • linear density
    Linear density
    Linear density, linear mass density or linear mass is a measure of mass per unit of length, and it is a characteristic of strings or other one-dimensional objects. The SI unit of linear density is the kilogram per metre...
    
    
  • ecliptic longitude in astrometry
    Astrometry
    Astrometry is the branch of astronomy that involves precise measurements of the positions and movements of stars and other celestial bodies. The information obtained by astrometric measurements provides information on the kinematics and physical origin of our Solar System and our Galaxy, the Milky...
    
    
  • the Liouville function in number theory
    Number theory
    Number theory is a branch of pure mathematics devoted primarily to the study of the integers. Number theorists study prime numbers as well...
    
    
  • the Carmichael function in number theory
    Number theory
    Number theory is a branch of pure mathematics devoted primarily to the study of the integers. Number theorists study prime numbers as well...
    
    
  • a unit of measure
    Unit of measure
    Unit of measure may refer to:* Units of measurement for relevance to weights and measures* Unit of account for relevance in economics* Unit of Measure , a 2000 album by Tony Rice...
    
     of volume
    Volume
    Volume is the quantity of three-dimensional space enclosed by some closed boundary, for example, the space that a substance or shape occupies or contains....
    
     equal to one microlitre (1 μL) or one cubic millimetre (1 mm³)
  • the empty string
    Empty string
    In computer science and formal language theory, the empty string is the unique string of length zero. It is denoted with λ or sometimes Λ or ε....
    
     in formal grammar
    Formal grammar
    A formal grammar is a set of formation rules for strings in a formal language. The rules describe how to form strings from the language's alphabet that are valid according to the language's syntax...
    
    

Μμ (mu)

• μ represents:
  • the Möbius function
    Möbius function
    The classical Möbius function μ is an important multiplicative function in number theory and combinatorics. The German mathematician August Ferdinand Möbius introduced it in 1832...
    
     in number theory
    Number theory
    Number theory is a branch of pure mathematics devoted primarily to the study of the integers. Number theorists study prime numbers as well...
    
    
  • the ring representation
    Representation (mathematics)
    In mathematics, representation is a very general relationship that expresses similarities between objects. Roughly speaking, a collection Y of mathematical objects may be said to represent another collection X of objects, provided that the properties and relationships existing among the...
    
     of a representation module
  • the population mean
    Mean
    In statistics, mean has two related meanings:* the arithmetic mean .* the expected value of a random variable, which is also called the population mean....
    
     or expected value
    Expected value
    In probability theory, the expected value of a random variable is the weighted average of all possible values that this random variable can take on...
    
     in probability
    Probability
    Probability is ordinarily used to describe an attitude of mind towards some proposition of whose truth we arenot certain. The proposition of interest is usually of the form "Will a specific event occur?" The attitude of mind is of the form "How certain are we that the event will occur?" The...
    
     and statistics
    Statistics
    Statistics is the study of the collection, organization, analysis, and interpretation of data. It deals with all aspects of this, including the planning of data collection in terms of the design of surveys and experiments....
    
    
  • a measure
    Measure (mathematics)
    In mathematical analysis, a measure on a set is a systematic way to assign to each suitable subset a number, intuitively interpreted as the size of the subset. In this sense, a measure is a generalization of the concepts of length, area, and volume...
    
     in measure theory
  • micro-, an SI prefix
    SI prefix
    The International System of Units specifies a set of unit prefixes known as SI prefixes or metric prefixes. An SI prefix is a name that precedes a basic unit of measure to indicate a decadic multiple or fraction of the unit. Each prefix has a unique symbol that is prepended to the unit symbol...
    
     denoting 10⁻⁶ (one millionth)
  • the coefficient of friction in physics
    Physics
    Physics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...
    
    
  • the service rate
    Service rate
    *In business, service rate is a performance metric used to measure the customer service in a supply organization. One example of a service rate measures the number of units filled as a percentage of the total ordered and is known as fill rate...
    
     in queueing theory
    Queueing theory
    Queueing theory is the mathematical study of waiting lines, or queues. The theory enables mathematical analysis of several related processes, including arriving at the queue, waiting in the queue , and being served at the front of the queue...
    
    
  • the dynamic viscosity in physics
  • magnetic permeability
    Permeability (electromagnetism)
    In electromagnetism, permeability is the measure of the ability of a material to support the formation of a magnetic field within itself. In other words, it is the degree of magnetization that a material obtains in response to an applied magnetic field. Magnetic permeability is typically...
    
     in electromagnetics
  • a muon
    Muon
    The muon |mu]] used to represent it) is an elementary particle similar to the electron, with a unitary negative electric charge and a spin of ½. Together with the electron, the tau, and the three neutrinos, it is classified as a lepton...
    
    
  • reduced mass
    Reduced mass
    Reduced mass is the "effective" inertial mass appearing in the two-body problem of Newtonian mechanics. This is a quantity with the unit of mass, which allows the two-body problem to be solved as if it were a one-body problem. Note however that the mass determining the gravitational force is not...
    
    
  • chemical potential in condensed matter
    Condensed Matter
    Condensed matter may refer to several things*Condensed matter physics, the study of the physical properties of condensed phases of matter*European Physical Journal B: Condensed Matter and Complex Systems, a scientific journal published by EDP sciences...
    
     physics

Νν (nu)

• ν represents:
  • frequency
    Frequency
    Frequency is the number of occurrences of a repeating event per unit time. It is also referred to as temporal frequency.The period is the duration of one cycle in a repeating event, so the period is the reciprocal of the frequency...
    
     in physics in hertz
    Hertz
    The hertz is the SI unit of frequency defined as the number of cycles per second of a periodic phenomenon. One of its most common uses is the description of the sine wave, particularly those used in radio and audio applications....
    
     (Hz)
  • Poisson's ratio
    Poisson's ratio
    Poisson's ratio , named after Siméon Poisson, is the ratio, when a sample object is stretched, of the contraction or transverse strain , to the extension or axial strain ....
    
     in material science
  • a neutrino
    Neutrino
    A neutrino is an electrically neutral, weakly interacting elementary subatomic particle with a half-integer spin, chirality and a disputed but small non-zero mass. It is able to pass through ordinary matter almost unaffected...
    
    
  • kinematic viscosity of liquids
  • stoichiometric coefficient in chemistry
  • dimension of nullspace in maths

Ξξ (xi)

• Ξ represents:
  • the grand canonical ensemble
    Grand canonical ensemble
    In statistical mechanics, a grand canonical ensemble is a theoretical collection of model systems put together to mirror the calculated probability distribution of microscopic states of a given physical system which is being maintained in a given macroscopic state...
    
     found in statistical mechanics
    Statistical mechanics
    Statistical mechanics or statistical thermodynamicsThe terms statistical mechanics and statistical thermodynamics are used interchangeably...
    
    
  • a type of baryon
• ξ represents:
  • a random variable
    Random variable
    In probability and statistics, a random variable or stochastic variable is, roughly speaking, a variable whose value results from a measurement on some type of random process. Formally, it is a function from a probability space, typically to the real numbers, which is measurable functionmeasurable...
    
    .
  • the extent of a chemical reaction
  • coherence length
    Coherence length
    In physics, coherence length is the propagation distance from a coherent source to a point where an electromagnetic wave maintains a specified degree of coherence. The significance is that interference will be strong within a coherence length of the source, but not beyond it...
    
    
  • the damping
    Damping
    In physics, damping is any effect that tends to reduce the amplitude of oscillations in an oscillatory system, particularly the harmonic oscillator.In mechanics, friction is one such damping effect...
    
     ratio
  • universal set

Οο (omicron)

• Ο represents:
  • big O notation
    Big O notation
    In mathematics, big O notation is used to describe the limiting behavior of a function when the argument tends towards a particular value or infinity, usually in terms of simpler functions. It is a member of a larger family of notations that is called Landau notation, Bachmann-Landau notation, or...
    
     (may be represented by an uppercase Latin O as well)

Ππ (pi)

• Π represents:
  • the product
    Multiplication
    Multiplication is the mathematical operation of scaling one number by another. It is one of the four basic operations in elementary arithmetic ....
    
     operator in mathematics
  • a plane
    Plane (mathematics)
    In mathematics, a plane is a flat, two-dimensional surface. A plane is the two dimensional analogue of a point , a line and a space...
    
    
• π represents:
  • Archimedes' constant, the ratio of a circle
    Circle
    A circle is a simple shape of Euclidean geometry consisting of those points in a plane that are a given distance from a given point, the centre. The distance between any of the points and the centre is called the radius....
    
    's circumference
    Circumference
    The circumference is the distance around a closed curve. Circumference is a special perimeter.-Circumference of a circle:The circumference of a circle is the length around it....
    
     to its diameter
    Diameter
    In geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints are on the circle. The diameters are the longest chords of the circle...
    
    
  • the prime-counting function
  • profit
    Profit (economics)
    In economics, the term profit has two related but distinct meanings. Normal profit represents the total opportunity costs of a venture to an entrepreneur or investor, whilst economic profit In economics, the term profit has two related but distinct meanings. Normal profit represents the total...
    
     in microeconomics
    Microeconomics
    Microeconomics is a branch of economics that studies the behavior of how the individual modern household and firms make decisions to allocate limited resources. Typically, it applies to markets where goods or services are being bought and sold...
    
     and game theory
    Game theory
    Game theory is a mathematical method for analyzing calculated circumstances, such as in games, where a person’s success is based upon the choices of others...
    
    
  • inflation
    Inflation
    In economics, inflation is a rise in the general level of prices of goods and services in an economy over a period of time.When the general price level rises, each unit of currency buys fewer goods and services. Consequently, inflation also reflects an erosion in the purchasing power of money – a...
    
     in macroeconomics
    Macroeconomics
    Macroeconomics is a branch of economics dealing with the performance, structure, behavior, and decision-making of the whole economy. This includes a national, regional, or global economy...
    
    , expressed as a constant with respect to time
  • the state distribution of a Markov chain
    Markov chain
    A Markov chain, named after Andrey Markov, is a mathematical system that undergoes transitions from one state to another, between a finite or countable number of possible states. It is a random process characterized as memoryless: the next state depends only on the current state and not on the...
    
    
  • a type of covalent bond
    Covalent bond
    A covalent bond is a form of chemical bonding that is characterized by the sharing of pairs of electrons between atoms. The stable balance of attractive and repulsive forces between atoms when they share electrons is known as covalent bonding....
    
     in chemistry (pi bond
    Pi bond
    In chemistry, pi bonds are covalent chemical bonds where two lobes of one involved atomic orbital overlap two lobes of the other involved atomic orbital...
    
    )
  • a pion
    Pion
    In particle physics, a pion is any of three subatomic particles: , , and . Pions are the lightest mesons and they play an important role in explaining the low-energy properties of the strong nuclear force....
    
     (pi meson) in particle physics
  • in electronics, a special type of small signal model
    Small signal model
    Small-signal modeling is a common analysis technique in electrical engineering which is used to approximate the behavior of nonlinear devices with linear equations...
    
     is referred to as a hybrid-pi model
    Hybrid-pi model
    The hybrid-pi model is a popular circuit model used for analyzing the small signal behavior of bipolar junction and field effect transistors. The model can be quite accurate for low-frequency circuits and can easily be adapted for higher frequency circuits with the addition of appropriate...
    
    
• ϖ (a graphic variant, see pomega) represents:
  • angular frequency
    Angular frequency
    In physics, angular frequency ω is a scalar measure of rotation rate. Angular frequency is the magnitude of the vector quantity angular velocity...
    
     of a wave
    Ocean surface wave
    In fluid dynamics, wind waves or, more precisely, wind-generated waves are surface waves that occur on the free surface of oceans, seas, lakes, rivers, and canals or even on small puddles and ponds. They usually result from the wind blowing over a vast enough stretch of fluid surface. Waves in the...
    
    , in fluid dynamics
    Fluid dynamics
    In physics, fluid dynamics is a sub-discipline of fluid mechanics that deals with fluid flow—the natural science of fluids in motion. It has several subdisciplines itself, including aerodynamics and hydrodynamics...
    
     (angular frequency is usually represented by but this may be confused with vorticity in a fluid dynamics context)
  • longitude of pericenter
    Longitude of the periapsis
    In astrodynamics, the longitude of the periapsis of an orbiting body is the longitude at which the periapsis would occur if the body's inclination were zero. For motion of a planet around the sun, this position could be called longitude of perihelion...
    
    , in celestial mechanics
    Celestial mechanics
    Celestial mechanics is the branch of astronomy that deals with the motions of celestial objects. The field applies principles of physics, historically classical mechanics, to astronomical objects such as stars and planets to produce ephemeris data. Orbital mechanics is a subfield which focuses on...
    
    
  • comoving distance
    Comoving distance
    In standard cosmology, comoving distance and proper distance are two closely related distance measures used by cosmologists to define distances between objects...
    
    , in cosmology

Ρρ (rho)

• ρ represents:
  • the radius
    Radius
    In classical geometry, a radius of a circle or sphere is any line segment from its center to its perimeter. By extension, the radius of a circle or sphere is the length of any such segment, which is half the diameter. If the object does not have an obvious center, the term may refer to its...
    
     in a polar
    Polar coordinate system
    In mathematics, the polar coordinate system is a two-dimensional coordinate system in which each point on a plane is determined by a distance from a fixed point and an angle from a fixed direction....
    
    , cylindrical
    Cylindrical coordinate system
    A cylindrical coordinate system is a three-dimensional coordinate systemthat specifies point positions by the distance from a chosen reference axis, the direction from the axis relative to a chosen reference direction, and the distance from a chosen reference plane perpendicular to the axis...
    
    , or spherical coordinate system
    Spherical coordinate system
    In mathematics, a spherical coordinate system is a coordinate system for three-dimensional space where the position of a point is specified by three numbers: the radial distance of that point from a fixed origin, its inclination angle measured from a fixed zenith direction, and the azimuth angle of...
    
    
  • the correlation coefficient
    Spearman's rank correlation coefficient
    In statistics, Spearman's rank correlation coefficient or Spearman's rho, named after Charles Spearman and often denoted by the Greek letter \rho or as r_s, is a non-parametric measure of statistical dependence between two variables. It assesses how well the relationship between two variables can...
    
     in statistics
    Statistics
    Statistics is the study of the collection, organization, analysis, and interpretation of data. It deals with all aspects of this, including the planning of data collection in terms of the design of surveys and experiments....
    
    
  • the sensitivity to interest rate in mathematical finance
    Mathematical finance
    Mathematical finance is a field of applied mathematics, concerned with financial markets. The subject has a close relationship with the discipline of financial economics, which is concerned with much of the underlying theory. Generally, mathematical finance will derive and extend the mathematical...
    
    
  • density
    Density
    The mass density or density of a material is defined as its mass per unit volume. The symbol most often used for density is ρ . In some cases , density is also defined as its weight per unit volume; although, this quantity is more properly called specific weight...
    
     (mass or charge per unit volume)
  • resistivity
    Resistivity
    Electrical resistivity is a measure of how strongly a material opposes the flow of electric current. A low resistivity indicates a material that readily allows the movement of electric charge. The SI unit of electrical resistivity is the ohm metre...
    
    
  • the shape and reshape operators in APL (in the form ⍴)
  • the utilization
    Utilization
    Utilization is a statistical concept as well as a primary business measure for the rental industry.-Queueing theory:In queueing theory, utilization is the proportion of the system's resources which is used by the traffic which arrives at it. It should be strictly less than one for the system to...
    
     in queueing theory
    Queueing theory
    Queueing theory is the mathematical study of waiting lines, or queues. The theory enables mathematical analysis of several related processes, including arriving at the queue, waiting in the queue , and being served at the front of the queue...
    
    
  • the rank of a matrix

Σσ (sigma)

• Σ represents:
  • the summation
    Summation
    Summation is the operation of adding a sequence of numbers; the result is their sum or total. If numbers are added sequentially from left to right, any intermediate result is a partial sum, prefix sum, or running total of the summation. The numbers to be summed may be integers, rational numbers,...
    
     operator
  • the covariance matrix
    Covariance matrix
    In probability theory and statistics, a covariance matrix is a matrix whose element in the i, j position is the covariance between the i th and j th elements of a random vector...
    
    
  • the set of terminal symbols in a formal grammar
    Formal grammar
    A formal grammar is a set of formation rules for strings in a formal language. The rules describe how to form strings from the language's alphabet that are valid according to the language's syntax...
    
    
• σ represents:
  • Stefan's constant in blackbody radiation
  • the divisor function
    Divisor function
    In mathematics, and specifically in number theory, a divisor function is an arithmetical function related to the divisors of an integer. When referred to as the divisor function, it counts the number of divisors of an integer. It appears in a number of remarkable identities, including relationships...
    
     in number theory
    Number theory
    Number theory is a branch of pure mathematics devoted primarily to the study of the integers. Number theorists study prime numbers as well...
    
    
  • the real part of the complex
    Complex number
    A complex number is a number consisting of a real part and an imaginary part. Complex numbers extend the idea of the one-dimensional number line to the two-dimensional complex plane by using the number line for the real part and adding a vertical axis to plot the imaginary part...
    
     variable s = σ + i t in analytic number theory
    Analytic number theory
    In mathematics, analytic number theory is a branch of number theory that uses methods from mathematical analysis to solve problems about the integers. It is often said to have begun with Dirichlet's introduction of Dirichlet L-functions to give the first proof of Dirichlet's theorem on arithmetic...
    
    
  • the sign of a permutation in the theory of finite groups
  • the population standard deviation
    Standard deviation
    Standard deviation is a widely used measure of variability or diversity used in statistics and probability theory. It shows how much variation or "dispersion" there is from the average...
    
     or spread
    Spread
    Spread may refer to:*Statistical dispersion*Spread , an edible paste put on other foods*the score difference being wagered on in spread betting*the measure of line inclination in rational trigonometry...
    
     in probability
    Probability
    Probability is ordinarily used to describe an attitude of mind towards some proposition of whose truth we arenot certain. The proposition of interest is usually of the form "Will a specific event occur?" The attitude of mind is of the form "How certain are we that the event will occur?" The...
    
     and statistics
    Statistics
    Statistics is the study of the collection, organization, analysis, and interpretation of data. It deals with all aspects of this, including the planning of data collection in terms of the design of surveys and experiments....
    
    
  • a type of covalent bond
    Covalent bond
    A covalent bond is a form of chemical bonding that is characterized by the sharing of pairs of electrons between atoms. The stable balance of attractive and repulsive forces between atoms when they share electrons is known as covalent bonding....
    
     in chemistry (sigma bond
    Sigma bond
    In chemistry, sigma bonds are the strongest type of covalent chemical bond. They are formed by head-on overlapping between atomic orbitals. Sigma bonding is most clearly defined for diatomic molecules using the language and tools of symmetry groups. In this formal approach, a σ-bond is...
    
    )
  • the selection operator in relational algebra
    Relational algebra
    Relational algebra, an offshoot of first-order logic , deals with a set of finitary relations that is closed under certain operators. These operators operate on one or more relations to yield a relation...
    
    
  • stress
    Stress (physics)
    In continuum mechanics, stress is a measure of the internal forces acting within a deformable body. Quantitatively, it is a measure of the average force per unit area of a surface within the body on which internal forces act. These internal forces are a reaction to external forces applied on the body...
    
     in mechanics
  • electrical conductivity
  • area density
  • nuclear cross section
    Nuclear cross section
    The nuclear cross section of a nucleus is used to characterize the probability that a nuclear reaction will occur. The concept of a nuclear cross section can be quantified physically in terms of "characteristic area" where a larger area means a larger probability of interaction...
    
    
  • uncertainty
  • utilization in operations management
  • surface charge
    Surface charge
    Surface charge is the electric charge present at an interface. There are many different processes which can lead to a surface being charged, including adsorption of ions, protonation/deprotonation, and the application of an external electric field...
    
     density for microparticles

Ττ (tau

Tau

Tau is the 19th letter of the Greek alphabet. In the system of Greek numerals it has a value of 300.The name in English is pronounced , but in modern Greek it is...

)

• τ (lower-case) represents:
  • an interval
    Interval
    Interval may refer to:* Interval , a range of numbers * Interval measurements or interval variables in statistics is a level of measurement...
    
     of time
  • a mean lifetime
  • torque
    Torque
    Torque, moment or moment of force , is the tendency of a force to rotate an object about an axis, fulcrum, or pivot. Just as a force is a push or a pull, a torque can be thought of as a twist....
    
    , the rotational force in mechanics
    Mechanics
    Mechanics is the branch of physics concerned with the behavior of physical bodies when subjected to forces or displacements, and the subsequent effects of the bodies on their environment....
    
    
  • the elementary tau lepton
    Tau lepton
    The tau , also called the tau lepton, tau particle or tauon, is an elementary particle similar to the electron, with negative electric charge and a spin of . Together with the electron, the muon, and the three neutrinos, it is classified as a lepton...
    
     in particle physics
    Particle physics
    Particle physics is a branch of physics that studies the existence and interactions of particles that are the constituents of what is usually referred to as matter or radiation. In current understanding, particles are excitations of quantum fields and interact following their dynamics...
    
    
  • the lifetime of a spontaneous emission
    Spontaneous emission
    Spontaneous emission is the process by which a light source such as an atom, molecule, nanocrystal or nucleus in an excited state undergoes a transition to a state with a lower energy, e.g., the ground state and emits a photon...
    
     process
  • the time constant
    Time constant
    In physics and engineering, the time constant, usually denoted by the Greek letter \tau , is the risetime characterizing the response to a time-varying input of a first-order, linear time-invariant system.Concretely, a first-order LTI system is a system that can be modeled by a single first order...
    
     of any device, such as an RC circuit
    RC circuit
    A resistor–capacitor circuit ', or RC filter or RC network, is an electric circuit composed of resistors and capacitors driven by a voltage or current source...
    
    
  • proper time
    Proper time
    In relativity, proper time is the elapsed time between two events as measured by a clock that passes through both events. The proper time depends not only on the events but also on the motion of the clock between the events. An accelerated clock will measure a smaller elapsed time between two...
    
     in relativity
    Theory of relativity
    The theory of relativity, or simply relativity, encompasses two theories of Albert Einstein: special relativity and general relativity. However, the word relativity is sometimes used in reference to Galilean invariance....
    
    
  • a correlation coefficient — see Kendall's tau
  • the golden ratio
    Golden ratio
    In mathematics and the arts, two quantities are in the golden ratio if the ratio of the sum of the quantities to the larger quantity is equal to the ratio of the larger quantity to the smaller one. The golden ratio is an irrational mathematical constant, approximately 1.61803398874989...
    
     1.618... (although φ
    Phi (letter)
    Phi , pronounced or sometimes in English, and in modern Greek, is the 21st letter of the Greek alphabet. In modern Greek, it represents , a voiceless labiodental fricative. In Ancient Greek it represented , an aspirated voiceless bilabial plosive...
    
     (phi) is more common)
  • Ramanujan's tau function in number theory
    Number theory
    Number theory is a branch of pure mathematics devoted primarily to the study of the integers. Number theorists study prime numbers as well...
    
    
  • in astronomy
    Astronomy
    Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...
    
    , a measure of opacity
    Opacity (optics)
    Opacity is the measure of impenetrability to electromagnetic or other kinds of radiation, especially visible light. In radiative transfer, it describes the absorption and scattering of radiation in a medium, such as a plasma, dielectric, shielding material, glass, etc...
    
    , or how much sunlight cannot penetrate the atmosphere
  • the intertwining operator in representation theory
  • the tau in biochemistry
    Biochemistry
    Biochemistry, sometimes called biological chemistry, is the study of chemical processes in living organisms, including, but not limited to, living matter. Biochemistry governs all living organisms and living processes...
    
    , a protein
    Protein
    Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
    
     associated to microtubule
    Microtubule
    Microtubules are a component of the cytoskeleton. These rope-like polymers of tubulin can grow as long as 25 micrometers and are highly dynamic. The outer diameter of microtubule is about 25 nm. Microtubules are important for maintaining cell structure, providing platforms for intracellular...
    
    s
  • shear
    Shear stress
    A shear stress, denoted \tau\, , is defined as the component of stress coplanar with a material cross section. Shear stress arises from the force vector component parallel to the cross section...
    
     stress
    Stress (physics)
    In continuum mechanics, stress is a measure of the internal forces acting within a deformable body. Quantitatively, it is a measure of the average force per unit area of a surface within the body on which internal forces act. These internal forces are a reaction to external forces applied on the body...
    
     in continuum mechanics
    Continuum mechanics
    Continuum mechanics is a branch of mechanics that deals with the analysis of the kinematics and the mechanical behavior of materials modelled as a continuous mass rather than as discrete particles...
    
    
  • the number of divisors of highly composite numbers
  • the prefix of many stars, via the Bayer
    Bayer designation
    A Bayer designation is a stellar designation in which a specific star is identified by a Greek letter, followed by the genitive form of its parent constellation's Latin name...
    
     stellar designation system
  • an internal system step in transition systems
    State transition system
    In theoretical computer science, a state transition system is an abstract machine used in the study of computation. The machine consists of a set of states and transitions between states, which may be labeled with labels chosen from a set; the same label may appear on more than one transition...
    
    
  • a type variable in type theories, such as the simply typed lambda calculus
    Simply typed lambda calculus
    The simply typed lambda calculus , a formof type theory, is a typed interpretation of the lambda calculus with only one type constructor: \to that builds function types. It is the canonical and simplest example of a typed lambda calculus...
    
    
  • 
    Tau (2π)
    Tau is a mathematical constant equal to the ratio of any circle's circumference to its radius, and has a value of approximately 6.28318531. This number also appears in many common formulas, often because it is the period of some very common functions — sine, cosine, , and others that involve...
    
     has been suggested as a circle constant to replace pi and has a value of 6.283..., or 2×π

Φφ (phi)

• Φ represents:
  • the work function
    Work function
    In solid-state physics, the work function is the minimum energy needed to remove an electron from a solid to a point immediately outside the solid surface...
    
     in physics; the energy required by a photon to remove an electron from the surface of a metal
  • magnetic flux
    Magnetic flux
    Magnetic flux , is a measure of the amount of magnetic B field passing through a given surface . The SI unit of magnetic flux is the weber...
    
    
  • the cumulative distribution function
    Cumulative distribution function
    In probability theory and statistics, the cumulative distribution function , or just distribution function, describes the probability that a real-valued random variable X with a given probability distribution will be found at a value less than or equal to x. Intuitively, it is the "area so far"...
    
     of the normal distribution in statistics
  • phenyl functional group
  • the reciprocal
    Reciprocal
    -In mathematics:*Multiplicative inverse, in mathematics, the number 1/x, which multiplied by x gives the product 1, also known as a reciprocal*Reciprocal rule, a technique in calculus for calculating derivatives of reciprocal functions...
    
     of the golden ratio
    Golden ratio
    In mathematics and the arts, two quantities are in the golden ratio if the ratio of the sum of the quantities to the larger quantity is equal to the ratio of the larger quantity to the smaller one. The golden ratio is an irrational mathematical constant, approximately 1.61803398874989...
    
     (represented by φ, below), also represented as 1/φ
  • note: a symbol for the empty set
    Empty set
    In mathematics, and more specifically set theory, the empty set is the unique set having no elements; its size or cardinality is zero. Some axiomatic set theories assure that the empty set exists by including an axiom of empty set; in other theories, its existence can be deduced...
    
    , , resembles Φ but is not Φ
• φ represents:
  • the golden ratio
    Golden ratio
    In mathematics and the arts, two quantities are in the golden ratio if the ratio of the sum of the quantities to the larger quantity is equal to the ratio of the larger quantity to the smaller one. The golden ratio is an irrational mathematical constant, approximately 1.61803398874989...
    
     1.618... in mathematics, art, and architecture
  • Euler's totient function
    Euler's totient function
    In number theory, the totient \varphi of a positive integer n is defined to be the number of positive integers less than or equal to n that are coprime to n In number theory, the totient \varphi(n) of a positive integer n is defined to be the number of positive integers less than or equal to n that...
    
     in number theory
  • a holomorphic map on an analytic space
  • the argument of a complex number
    Complex number
    A complex number is a number consisting of a real part and an imaginary part. Complex numbers extend the idea of the one-dimensional number line to the two-dimensional complex plane by using the number line for the real part and adding a vertical axis to plot the imaginary part...
    
     in mathematics
  • the value of a plane angle
    Angle
    In geometry, an angle is the figure formed by two rays sharing a common endpoint, called the vertex of the angle.Angles are usually presumed to be in a Euclidean plane with the circle taken for standard with regard to direction. In fact, an angle is frequently viewed as a measure of an circular arc...
    
     in physics and mathematics
  • the angle
    Angle
    In geometry, an angle is the figure formed by two rays sharing a common endpoint, called the vertex of the angle.Angles are usually presumed to be in a Euclidean plane with the circle taken for standard with regard to direction. In fact, an angle is frequently viewed as a measure of an circular arc...
    
     to the z axis in spherical coordinates
  • latitude
    Latitude
    In geography, the latitude of a location on the Earth is the angular distance of that location south or north of the Equator. The latitude is an angle, and is usually measured in degrees . The equator has a latitude of 0°, the North pole has a latitude of 90° north , and the South pole has a...
    
     in geodesy
    Geodesy
    Geodesy , also named geodetics, a branch of earth sciences, is the scientific discipline that deals with the measurement and representation of the Earth, including its gravitational field, in a three-dimensional time-varying space. Geodesists also study geodynamical phenomena such as crustal...
    
    
  • a scalar field
    Scalar field
    In mathematics and physics, a scalar field associates a scalar value to every point in a space. The scalar may either be a mathematical number, or a physical quantity. Scalar fields are required to be coordinate-independent, meaning that any two observers using the same units will agree on the...
    
    
  • radiant flux
    Radiant flux
    In radiometry, radiant flux or radiant power is the measure of the total power of electromagnetic radiation...
    
    
  • electric potential
    Electric potential
    In classical electromagnetism, the electric potential at a point within a defined space is equal to the electric potential energy at that location divided by the charge there...
    
    
  • the probability density function
    Probability density function
    In probability theory, a probability density function , or density of a continuous random variable is a function that describes the relative likelihood for this random variable to occur at a given point. The probability for the random variable to fall within a particular region is given by the...
    
     of the normal distribution in statistics
  • a feature of a syntactic node giving that node characteristics such as gender
    Grammatical gender
    Grammatical gender is defined linguistically as a system of classes of nouns which trigger specific types of inflections in associated words, such as adjectives, verbs and others. For a system of noun classes to be a gender system, every noun must belong to one of the classes and there should be...
    
    , number
    Grammatical number
    In linguistics, grammatical number is a grammatical category of nouns, pronouns, and adjective and verb agreement that expresses count distinctions ....
    
     and person
    Grammatical person
    Grammatical person, in linguistics, is deictic reference to a participant in an event; such as the speaker, the addressee, or others. Grammatical person typically defines a language's set of personal pronouns...
    
     in syntax
    Syntax
    In linguistics, syntax is the study of the principles and rules for constructing phrases and sentences in natural languages....
    
    

Χχ (chi)

• χ represents:
  • the chi distribution in statistics
    Statistics
    Statistics is the study of the collection, organization, analysis, and interpretation of data. It deals with all aspects of this, including the planning of data collection in terms of the design of surveys and experiments....
    
     (χ is the more frequently encountered chi-squared distribution)
  • the chromatic number of a graph in graph theory
    Graph theory
    In mathematics and computer science, graph theory is the study of graphs, mathematical structures used to model pairwise relations between objects from a certain collection. A "graph" in this context refers to a collection of vertices or 'nodes' and a collection of edges that connect pairs of...
    
    
  • the Euler characteristic
    Euler characteristic
    In mathematics, and more specifically in algebraic topology and polyhedral combinatorics, the Euler characteristic is a topological invariant, a number that describes a topological space's shape or structure regardless of the way it is bent...
    
     in algebraic topology
    Algebraic topology
    Algebraic topology is a branch of mathematics which uses tools from abstract algebra to study topological spaces. The basic goal is to find algebraic invariants that classify topological spaces up to homeomorphism, though usually most classify up to homotopy equivalence.Although algebraic topology...
    
    
  • a variable in algebraic
    Algebraic
    Algebraic may refer to any subject within the algebra branch of mathematics and related branches like algebraic geometry and algebraic topology.Algebraic may also refer to:...
    
     equations
  • electronegativity
    Electronegativity
    Electronegativity, symbol χ , is a chemical property that describes the tendency of an atom or a functional group to attract electrons towards itself. An atom's electronegativity is affected by both its atomic number and the distance that its valence electrons reside from the charged nucleus...
    
     in the periodic table
    Periodic table
    The periodic table of the chemical elements is a tabular display of the 118 known chemical elements organized by selected properties of their atomic structures. Elements are presented by increasing atomic number, the number of protons in an atom's atomic nucleus...
    
    
  • the Rabi frequency
    Rabi frequency
    The Rabi frequency is the frequency of population oscillation for a given atomic transition in a given light field. It is associated with the strength of the coupling between the light and the transition. Rabi flopping between the levels of a 2-level system illuminated with resonant light, will...
    
    
  • the spinor
    Spinor
    In mathematics and physics, in particular in the theory of the orthogonal groups , spinors are elements of a complex vector space introduced to expand the notion of spatial vector. Unlike tensors, the space of spinors cannot be built up in a unique and natural way from spatial vectors...
    
     of a fundamental particle
  • the Fourier transform of a linear response function
    Linear response function
    A linear response function describes the input-output relationship of a signal transducer such as a radio turning electromagnetic waves into music or a neuron turning synaptic input into a response...
    
     (see susceptibility
    Susceptibility
    *In physics, the susceptibility of a material or substance describes its response to an applied field. There are many kinds of susceptibilities, for example:These two susceptibilities are particular examples of a linear response function;...
    
    )
  • a character
    Character (mathematics)
    In mathematics, a character is a special kind of function from a group to a field . There are at least two distinct, but overlapping meanings...
    
     in mathematics
    Mathematics
    Mathematics is the study of quantity, space, structure, and change. Mathematicians seek out patterns and formulate new conjectures. Mathematicians resolve the truth or falsity of conjectures by mathematical proofs, which are arguments sufficient to convince other mathematicians of their validity...
    
    ; especially a Dirichlet character
    Dirichlet character
    In number theory, Dirichlet characters are certain arithmetic functions which arise from completely multiplicative characters on the units of \mathbb Z / k \mathbb Z...
    
     in number theory
    Number theory
    Number theory is a branch of pure mathematics devoted primarily to the study of the integers. Number theorists study prime numbers as well...
    
    
  • the Sigma vectors in the unscented transform
    Unscented transform
    The Unscented Transform is a mathematical function used to estimate the result of applying a given nonlinear transformation to a probability distribution that is characterized only in terms of a finite set of statistics...
    
     used in the unscented Kalman filter
  • sometimes the mole fraction
  • a characteristic or indicator function in mathematics

Ψψ (psi)

• Ψ represents:
  • water potential
    Water potential
    Water potential is the potential energy of water per unit volume relative to pure water in reference conditions. Water potential quantifies the tendency of water to move from one area to another due to osmosis, gravity, mechanical pressure, or matrix effects such as surface tension...
    
    
  • a quaternary combinator in combinatory logic
    Combinatory logic
    Combinatory logic is a notation introduced by Moses Schönfinkel and Haskell Curry to eliminate the need for variables in mathematical logic. It has more recently been used in computer science as a theoretical model of computation and also as a basis for the design of functional programming...
    
    
• ψ represents:
  • the wave function in the Schrödinger equation
    Schrödinger equation
    The Schrödinger equation was formulated in 1926 by Austrian physicist Erwin Schrödinger. Used in physics , it is an equation that describes how the quantum state of a physical system changes in time....
    
     of quantum mechanics
    Quantum mechanics
    Quantum mechanics, also known as quantum physics or quantum theory, is a branch of physics providing a mathematical description of much of the dual particle-like and wave-like behavior and interactions of energy and matter. It departs from classical mechanics primarily at the atomic and subatomic...
    
    
  • the stream function
    Stream function
    The stream function is defined for two-dimensional flows of various kinds. The stream function can be used to plot streamlines, which represent the trajectories of particles in a steady flow. Streamlines are perpendicular to equipotential lines...
    
     in fluid dynamics
  • yaw angle in vehicle dynamics
  • the angle between the x-axis and the tangent to the curve in the intrinsic coordinates system
  • the second Chebyshev function
    Chebyshev function
    [Image:ChebyshevPsi.png|thumb|right|The Chebyshev function ψ, with x [Image:ChebyshevPsi.png|thumb|right|The Chebyshev function ψ, with x ...
    
     in number theory
    Number theory
    Number theory is a branch of pure mathematics devoted primarily to the study of the integers. Number theorists study prime numbers as well...
    
    

Ωω (omega)

• Ω represents:
  • the Omega constant
  • an asymptotic lower bound related to big O notation
    Big O notation
    In mathematics, big O notation is used to describe the limiting behavior of a function when the argument tends towards a particular value or infinity, usually in terms of simpler functions. It is a member of a larger family of notations that is called Landau notation, Bachmann-Landau notation, or...
    
    
  • in probability theory
    Probability theory
    Probability theory is the branch of mathematics concerned with analysis of random phenomena. The central objects of probability theory are random variables, stochastic processes, and events: mathematical abstractions of non-deterministic events or measured quantities that may either be single...
    
     and statistical mechanics
    Statistical mechanics
    Statistical mechanics or statistical thermodynamicsThe terms statistical mechanics and statistical thermodynamics are used interchangeably...
    
    , the set of possible distinct system states
  • the SI unit measure of electric resistance, the ohm
  • the rotation rate of an object, particularly a planet, in dynamics
  • a solid angle
    Solid angle
    The solid angle, Ω, is the two-dimensional angle in three-dimensional space that an object subtends at a point. It is a measure of how large that object appears to an observer looking from that point...
    
    
  • a baryon
    Baryon
    A baryon is a composite particle made up of three quarks . Baryons and mesons belong to the hadron family, which are the quark-based particles...
    
    
  • the arithmetic function counting a number's prime factors
  • the right ascension of the ascending node in celestial mechanics
    Celestial mechanics
    Celestial mechanics is the branch of astronomy that deals with the motions of celestial objects. The field applies principles of physics, historically classical mechanics, to astronomical objects such as stars and planets to produce ephemeris data. Orbital mechanics is a subfield which focuses on...
    
    
  • the density parameter in cosmology
    Physical cosmology
    Physical cosmology, as a branch of astronomy, is the study of the largest-scale structures and dynamics of the universe and is concerned with fundamental questions about its formation and evolution. For most of human history, it was a branch of metaphysics and religion...
    
    
• ω represents:
  • the first infinite ordinal
    Ordinal number
    In set theory, an ordinal number, or just ordinal, is the order type of a well-ordered set. They are usually identified with hereditarily transitive sets. Ordinals are an extension of the natural numbers different from integers and from cardinals...
    
    
  • the set of natural number
    Natural number
    In mathematics, the natural numbers are the ordinary whole numbers used for counting and ordering . These purposes are related to the linguistic notions of cardinal and ordinal numbers, respectively...
    
    s in set theory
    Set theory
    Set theory is the branch of mathematics that studies sets, which are collections of objects. Although any type of object can be collected into a set, set theory is applied most often to objects that are relevant to mathematics...
    
     (although or N is more common in other areas of mathematics)
  • an asymptotically dominant quantity related to big O notation
    Big O notation
    In mathematics, big O notation is used to describe the limiting behavior of a function when the argument tends towards a particular value or infinity, usually in terms of simpler functions. It is a member of a larger family of notations that is called Landau notation, Bachmann-Landau notation, or...
    
    
  • in probability theory
    Probability theory
    Probability theory is the branch of mathematics concerned with analysis of random phenomena. The central objects of probability theory are random variables, stochastic processes, and events: mathematical abstractions of non-deterministic events or measured quantities that may either be single...
    
    , a possible outcome of an experiment
  • angular velocity
    Angular velocity
    In physics, the angular velocity is a vector quantity which specifies the angular speed of an object and the axis about which the object is rotating. The SI unit of angular velocity is radians per second, although it may be measured in other units such as degrees per second, revolutions per...
    
     / radian frequency
    Angular velocity
    In physics, the angular velocity is a vector quantity which specifies the angular speed of an object and the axis about which the object is rotating. The SI unit of angular velocity is radians per second, although it may be measured in other units such as degrees per second, revolutions per...
    
    
  • a complex
    Complex number
    A complex number is a number consisting of a real part and an imaginary part. Complex numbers extend the idea of the one-dimensional number line to the two-dimensional complex plane by using the number line for the real part and adding a vertical axis to plot the imaginary part...
    
     cube root
    Root of unity
    In mathematics, a root of unity, or de Moivre number, is any complex number that equals 1 when raised to some integer power n. Roots of unity are used in many branches of mathematics, and are especially important in number theory, the theory of group characters, field theory, and the discrete...
    
     of unity — the other is ω² — (used to describe various ways of calculating the discrete Fourier transform
    Discrete Fourier transform
    In mathematics, the discrete Fourier transform is a specific kind of discrete transform, used in Fourier analysis. It transforms one function into another, which is called the frequency domain representation, or simply the DFT, of the original function...
    
    )
  • vertical velocity in pressure-based
    Geopotential height
    Geopotential height is a vertical coordinate referenced to Earth's mean sea level — an adjustment to geometric height using the variation of gravity with latitude and elevation. Thus it can be considered a "gravity-adjusted height"...
    
     coordinate systems (commonly used in atmospheric dynamics)
  • a meson
    Meson
    In particle physics, mesons are subatomic particles composed of one quark and one antiquark, bound together by the strong interaction. Because mesons are composed of sub-particles, they have a physical size, with a radius roughly one femtometer: 10−15 m, which is about the size of a proton...
    
    
  • the arithmetic function counting a number's distinct prime factors
  • a differential form (esp. on an analytic space)
  • the argument of periapsis
    Argument of periapsis
    The argument of periapsis , symbolized as ω, is one of the orbital elements of an orbiting body...
    
     in celestial mechanics
    Celestial mechanics
    Celestial mechanics is the branch of astronomy that deals with the motions of celestial objects. The field applies principles of physics, historically classical mechanics, to astronomical objects such as stars and planets to produce ephemeris data. Orbital mechanics is a subfield which focuses on...
    
    
  • the symbol ϖ, a graphic variant of π, is sometimes construed as omega with a bar over it; see π

See also

• Greek alphabet
  Greek alphabet
  The Greek alphabet is the script that has been used to write the Greek language since at least 730 BC . The alphabet in its classical and modern form consists of 24 letters ordered in sequence from alpha to omega...
  
  
• English pronunciation of Greek letters
  English pronunciation of Greek letters
  This table gives the common English pronunciation of Greek letters using the International Phonetic Alphabet It is the pronunciation of the ancient Greek names of the Greek letters using the English teaching pronunciation...
  
  
• A pronunciation guide with audio
• Latin letters used in mathematics
• Mathematical alphanumeric symbols
  Mathematical alphanumeric symbols
  Mathematical Alphanumeric Symbols is a Unicode block of Latin and Greek letters and decimal digits that enable mathematicians to denote different notions with different letter styles .Unicode now includes many such symbols Mathematical Alphanumeric Symbols is a Unicode block of Latin and Greek...
  
  
• Table of mathematical symbols
  Table of mathematical symbols
  This is a listing of common symbols found within all branches of mathematics. Each symbol is listed in both HTML, which depends on appropriate fonts being installed, and in , as an image.-Symbols:-Variations:...
  
  
• Typographical conventions in mathematical formulae
  Typographical conventions in mathematical formulae
  Typographical conventions in mathematical formulae provide uniformity across mathematical texts and help the readers of those texts to grasp new concepts quickly....
  
  
• The Greeks (Greek letters used in mathematical finance)