Symbol (typeface)
Encyclopedia
Symbol is one of the four standard fonts available on all PostScript
-based printers, starting with Apple's original LaserWriter
(1985). It contains a complete unaccented Greek alphabet
(upper and lower case) and a selection of commonly used mathematical symbols. Insofar as it fits into any standard classification, it is a serif
font designed in the style of Times Roman
.
Due to its non-standard character set, lack of diacritical characters, and type design inappropriate for continuous text, Symbol cannot easily be used for setting Greek language
text, though it has been used for that purpose in the absence of proper Greek fonts. Its primary purpose is to typeset mathematical
expressions.
, with the Greek letters arranged according to similar Latin letters (Chi
= C
, etc.). The document describing the mapping to Unicode code points was created before several of the characters were added to Unicode, so the original mapping assigns several of the characters to the Private Use Area (PUA). A later version of the font by Apple
uses more recently introduced Unicode code points instead. The table below mostly follows the Apple mapping.
~
80
unused
90
A0
€
ϒ
|ʹ
≤
⁄
∞
ƒ
♣
♦
♥
♠
↔
←
↑
→
↓
B0
°
±
|ʺ
≥
×
∝
∂
•
÷
≠
≡
≈
…
⏐
⎯
↵
C0
ℵ
ℑ
ℜ
℘
⊗
⊕
∅
∩
∪
⊃
⊇
⊄
⊂
⊆
∈
∉
D0
∠
∇
©
™
∏
√
⋅
¬
∧
∨
⇔
⇐
⇑
⇒
⇓
E0
◊
〈
®
©
™
∑
⎛
⎜
⎝
⎡
⎢
⎣
⎧
⎨
⎩
⎪
F0
〉
∫
⌠
⎮
⌡
⎞
⎟
⎠
⎤
⎥
⎦
⎫
⎬
⎭
The characters ®, ©, and ™ are encoded twice: one version has serif
s, the other (highlighted in yellow) is sans-serif
. The Adobe mapping uses PUA for all six characters to ensure that the presence or absence of serifs is observed, while the Apple font maps the serif versions to the standard Unicode code points and the sans-serif versions to PUA code points (but not the same ones Adobe used).
The character at 0x60 (highlighted in red) does not appear in Unicode. It is described in the Adobe map as "RADICAL
EXTENDER", with the Adobe glyph name "radicalex", and is mapped to the PUA code point U+F8E5. It is an over-bar for extending the radical sign over the operands of the radical operator. Some versions of the font implement this as a non-spacing character so that it can be combined (like non-spacing diacritical marks) with the operands it covers.
Beyond the use of Private Use Area code points, Adobe and Apple have a few other minor differences in code point assignments. Character 0x27 (called "suchthat" in the Adobe document) is assigned by Adobe to U+220B but by Apple to U+220D , which more closely resembles the symbol usually used for such that. Characters 0xE1 and 0xF1 are assigned to different sets of angle brackets: by Adobe to U+2329 and U+232A ( and ), by Apple to U+3008 and U+3009 ( and ). Apple also introduces the Apple logo as PUA code point U+F8FF
for character 0xF0, a position not used in the original Adobe font (and not assigned in the table above).
Lowercase Greek letters appear in italics
in many older versions of Symbol. While both Adobe and Apple agree on assigning characters 0x66 and 0x6A respectively to Unicode code points U+03C6 and U+03D5 , some versions of the font interchange these two symbols.
*encoded as ASCII
for older browsers
has included Symbols (in this specific case, sometimes referred to as "symbols.ttf") as a core font at least as far back as Windows 3.1x
.
for HTML 4.
At the time of that original recommendation (December 1997) the only native way to display many mathematical symbols in HTML
was a direct use of the "Symbol" font. Such explicit references are now strongly discouraged for new documents but they survive in many existing pages on the Internet
. Also, the Symbol font provides graphics that are specifically intended as components in the two-dimensional layout of mathematical expressions. Examples include upper and lower parts of brackets or integral signs and an indispensable square-root sign without a vinculum...
Until 2010 or so, the Unicode
glyph U+221A corresponding to that crucial square-root sign (the HTML entity is named radic and has decimal code 8730) was usually rendered with a short built-in vinculum. That made it an inadequate graphical replacement for the original character from the Symbol font (itself designed around a slanted line extending all the way to the upper-right corner of the character box, without any spacing). The more recent renditions of the HTML radic entity (U+221A) no longer feature any vinculum and are thus more compatible with the standard graphical representation introduced in the Symbol font. Both styles of the square-root glyph
(with or without a short vinculum) have the same disembodied meaning, so the integrity of the Unicode
repertoire is not compromised by this welcome adjustment.
Full legacy
support of the Symbol font is provided by major modern web browsers like Internet Explorer
and Google Chrome
. That support involves a specific handling of Adobe's special encoding, which is not properly implemented in at least some versions of other browsers, including Opera
, Safari
and Firefox. Such browsers do not correctly render legacy
HTML documents that make explicit use of the Symbol font.
PostScript
PostScript is a dynamically typed concatenative programming language created by John Warnock and Charles Geschke in 1982. It is best known for its use as a page description language in the electronic and desktop publishing areas. Adobe PostScript 3 is also the worldwide printing and imaging...
-based printers, starting with Apple's original LaserWriter
LaserWriter
The LaserWriter was a laser printer with built-in PostScript interpreter introduced by Apple in 1985. It was one of the first laser printers available to the mass market...
(1985). It contains a complete unaccented 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...
(upper and lower case) and a selection of commonly used mathematical symbols. Insofar as it fits into any standard classification, it is a serif
Serif
In typography, serifs are semi-structural details on the ends of some of the strokes that make up letters and symbols. A typeface with serifs is called a serif typeface . A typeface without serifs is called sans serif or sans-serif, from the French sans, meaning “without”...
font designed in the style of Times Roman
Times Roman
Times New Roman is a serif typeface commissioned by the British newspaper The Times in 1931, created by Victor Lardent at the English branch of Monotype. It was commissioned after Stanley Morison had written an article criticizing The Times for being badly printed and typographically antiquated...
.
Due to its non-standard character set, lack of diacritical characters, and type design inappropriate for continuous text, Symbol cannot easily be used for setting 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, though it has been used for that purpose in the absence of proper Greek fonts. Its primary purpose is to typeset mathematical
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...
expressions.
Encoding
The font was created by Adobe and has its own character encodingCharacter encoding
A character encoding system consists of a code that pairs each character from a given repertoire with something else, such as a sequence of natural numbers, octets or electrical pulses, in order to facilitate the transmission of data through telecommunication networks or storage of text in...
, with the Greek letters arranged according to similar Latin letters (Chi
Chi (letter)
Chi is the 22nd letter of the Greek alphabet, pronounced as in English.-Greek:-Ancient Greek:Its value in Ancient Greek was an aspirated velar stop .-Koine Greek:...
= C
C
Ĉ or ĉ is a consonant in Esperanto orthography, representing the sound .Esperanto orthography uses a diacritic for all four of its postalveolar consonants, as do the Latin-based Slavic alphabets...
, etc.). The document describing the mapping to Unicode code points was created before several of the characters were added to Unicode, so the original mapping assigns several of the characters to the Private Use Area (PUA). A later version of the font by Apple
Apple Computer
Apple Inc. is an American multinational corporation that designs and markets consumer electronics, computer software, and personal computers. The company's best-known hardware products include the Macintosh line of computers, the iPod, the iPhone and the iPad...
uses more recently introduced Unicode code points instead. The table below mostly follows the Apple mapping.
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | A | B | C | D | E | F | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 20 | ! | ∀ | # | ∃ | % | & | ( | ) | * | , | ||||||
| . | / | |||||||||||||||
| 30 | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | : | ; | < | = | > | ? |
| 40 | ≅ | Α | Β | Χ | Δ | Ε | Φ | Γ | Η | Ι | Κ | Λ | Μ | Ν | Ο | |
| 50 | Π | Θ | Ρ | Σ | Τ | Υ | ς | Ω | Ξ | Ψ | Ζ | [ | ∴ | ] | ⊥ | _ |
| 60 | #xF8E5; | α | β | χ | δ | ε | φ | γ | η | ι | κ | λ | μ | ν | ο | |
| 70 | π | θ | ρ | σ | τ | υ | ω | ξ | ψ | ζ | { | | |
|ʹ
|ʺ
The characters ®, ©, and ™ are encoded twice: one version has serif
Serif
In typography, serifs are semi-structural details on the ends of some of the strokes that make up letters and symbols. A typeface with serifs is called a serif typeface . A typeface without serifs is called sans serif or sans-serif, from the French sans, meaning “without”...
s, the other (highlighted in yellow) is sans-serif
Sans-serif
In typography, a sans-serif, sans serif or san serif typeface is one that does not have the small projecting features called "serifs" at the end of strokes. The term comes from the French word sans, meaning "without"....
. The Adobe mapping uses PUA for all six characters to ensure that the presence or absence of serifs is observed, while the Apple font maps the serif versions to the standard Unicode code points and the sans-serif versions to PUA code points (but not the same ones Adobe used).
The character at 0x60 (highlighted in red) does not appear in Unicode. It is described in the Adobe map as "RADICAL
Nth root
In mathematics, the nth root of a number x is a number r which, when raised to the power of n, equals xr^n = x,where n is the degree of the root...
EXTENDER", with the Adobe glyph name "radicalex", and is mapped to the PUA code point U+F8E5. It is an over-bar for extending the radical sign over the operands of the radical operator. Some versions of the font implement this as a non-spacing character so that it can be combined (like non-spacing diacritical marks) with the operands it covers.
Beyond the use of Private Use Area code points, Adobe and Apple have a few other minor differences in code point assignments. Character 0x27 (called "suchthat" in the Adobe document) is assigned by Adobe to U+220B but by Apple to U+220D , which more closely resembles the symbol usually used for such that. Characters 0xE1 and 0xF1 are assigned to different sets of angle brackets: by Adobe to U+2329 and U+232A ( and ), by Apple to U+3008 and U+3009 ( and ). Apple also introduces the Apple logo as PUA code point U+F8FF
U+F8FF
Unicode code point U+F8FF or is the last code point in the Private Use Area in BMP. Its meaning and appearance vary depending on the font in use, but its usage in several fonts makes it the most notable code point in the private use area....
for character 0xF0, a position not used in the original Adobe font (and not assigned in the table above).
Lowercase Greek letters appear in italics
Italic type
In typography, italic type is a cursive typeface based on a stylized form of calligraphic handwriting. Owing to the influence from calligraphy, such typefaces often slant slightly to the right. Different glyph shapes from roman type are also usually used—another influence from calligraphy...
in many older versions of Symbol. While both Adobe and Apple agree on assigning characters 0x66 and 0x6A respectively to Unicode code points U+03C6 and U+03D5 , some versions of the font interchange these two symbols.
Font comparison
| Uppercase | |||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Default | Α | Β | Γ | Δ | Ε | Ζ | Η | Θ | Ι | Κ | Λ | Μ | Ν | Ξ | Ο | Π | Ρ | Σ | Τ | Υ | Φ | Χ | Ψ | Ω | |
| Times | Α | Β | Γ | Δ | Ε | Ζ | Η | Θ | Ι | Κ | Λ | Μ | Ν | Ξ | Ο | Π | Ρ | Σ | Τ | Υ | Φ | Χ | Ψ | Ω | |
| Symbol | Α | Β | Γ | Δ | Ε | Ζ | Η | Θ | Ι | Κ | Λ | Μ | Ν | Ξ | Ο | Π | Ρ | Σ | Τ | Υ | Φ | Χ | Ψ | Ω | |
| Symbol* | A | B | G | D | E | Z | H | Q | I | K | L | M | N | X | O | P | R | S | T | U | F | C | Y | W | |
| Lowercase | |||||||||||||||||||||||||
| Default | α | β | γ | δ | ε | ζ | η | θ | ι | κ | λ | μ | ν | ξ | ο | π | ρ | ς | σ | τ | υ | φ | χ | ψ | ω |
| Times | α | β | γ | δ | ε | ζ | η | θ | ι | κ | λ | μ | ν | ξ | ο | π | ρ | ς | σ | τ | υ | φ | χ | ψ | ω |
| Symbol | α | β | γ | δ | ε | ζ | η | θ | ι | κ | λ | μ | ν | ξ | ο | π | ρ | ς | σ | τ | υ | φ | χ | ψ | ω |
| Symbol* | a | b | g | d | e | z | h | q | i | k | l | m | n | x | o | p | r | V | s | t | u | f | c | y | w |
*encoded as ASCII
ASCII
The American Standard Code for Information Interchange is a character-encoding scheme based on the ordering of the English alphabet. ASCII codes represent text in computers, communications equipment, and other devices that use text...
for older browsers
In Microsoft Windows
Microsoft WindowsMicrosoft Windows
Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...
has included Symbols (in this specific case, sometimes referred to as "symbols.ttf") as a core font at least as far back as Windows 3.1x
Windows 3.1x
Windows 3.1x is a series of 16-bit operating systems produced by Microsoft for use on personal computers. The series began with Windows 3.1, which was first sold during March 1992 as a successor to Windows 3.0...
.
HTML
The use of the Symbol font in mathematical expressions was part of a W3C recommendationW3C recommendation
A W3C Recommendation is the final stage of a ratification process of the World Wide Web Consortium working group concerning a technical standard. This designation signifies that a document has been subjected to a public and W3C-member organization's review. It aims to standardise the Web technology...
for HTML 4.
At the time of that original recommendation (December 1997) the only native way to display many mathematical symbols in HTML
HTML
HyperText Markup Language is the predominant markup language for web pages. HTML elements are the basic building-blocks of webpages....
was a direct use of the "Symbol" font. Such explicit references are now strongly discouraged for new documents but they survive in many existing pages on the Internet
Internet
The Internet is a global system of interconnected computer networks that use the standard Internet protocol suite to serve billions of users worldwide...
. Also, the Symbol font provides graphics that are specifically intended as components in the two-dimensional layout of mathematical expressions. Examples include upper and lower parts of brackets or integral signs and an indispensable square-root sign without a vinculum...
Until 2010 or so, the Unicode
Unicode
Unicode is a computing industry standard for the consistent encoding, representation and handling of text expressed in most of the world's writing systems...
glyph U+221A corresponding to that crucial square-root sign (the HTML entity is named radic and has decimal code 8730) was usually rendered with a short built-in vinculum. That made it an inadequate graphical replacement for the original character from the Symbol font (itself designed around a slanted line extending all the way to the upper-right corner of the character box, without any spacing). The more recent renditions of the HTML radic entity (U+221A) no longer feature any vinculum and are thus more compatible with the standard graphical representation introduced in the Symbol font. Both styles of the square-root 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....
(with or without a short vinculum) have the same disembodied meaning, so the integrity of the Unicode
Unicode
Unicode is a computing industry standard for the consistent encoding, representation and handling of text expressed in most of the world's writing systems...
repertoire is not compromised by this welcome adjustment.
Full legacy
Legacy system
A legacy system is an old method, technology, computer system, or application program that continues to be used, typically because it still functions for the users' needs, even though newer technology or more efficient methods of performing a task are now available...
support of the Symbol font is provided by major modern web browsers like Internet Explorer
Internet Explorer
Windows Internet Explorer is a series of graphical web browsers developed by Microsoft and included as part of the Microsoft Windows line of operating systems, starting in 1995. It was first released as part of the add-on package Plus! for Windows 95 that year...
and Google Chrome
Google Chrome
Google Chrome is a web browser developed by Google that uses the WebKit layout engine. It was first released as a beta version for Microsoft Windows on September 2, 2008, and the public stable release was on December 11, 2008. The name is derived from the graphical user interface frame, or...
. That support involves a specific handling of Adobe's special encoding, which is not properly implemented in at least some versions of other browsers, including Opera
Opera (web browser)
Opera is a web browser and Internet suite developed by Opera Software with over 200 million users worldwide. The browser handles common Internet-related tasks such as displaying web sites, sending and receiving e-mail messages, managing contacts, chatting on IRC, downloading files via BitTorrent,...
, Safari
Safari (web browser)
Safari is a web browser developed by Apple Inc. and included with the Mac OS X and iOS operating systems. First released as a public beta on January 7, 2003 on the company's Mac OS X operating system, it became Apple's default browser beginning with Mac OS X v10.3 "Panther". Safari is also the...
and Firefox. Such browsers do not correctly render legacy
Legacy system
A legacy system is an old method, technology, computer system, or application program that continues to be used, typically because it still functions for the users' needs, even though newer technology or more efficient methods of performing a task are now available...
HTML documents that make explicit use of the Symbol font.