East is a noun

Noun

In linguistics, a noun is a member of a large, open lexical category whose members can occur as the main word in the subject of a clause, the object of a verb, or the object of a preposition .Lexical categories are defined in terms of how their members combine with other kinds of...

, adjective

Adjective

In grammar, an adjective is a 'describing' word; the main syntactic role of which is to qualify a noun or noun phrase, giving more information about the object signified....

, or adverb

Adverb

An adverb is a part of speech that modifies verbs or any part of speech other than a noun . Adverbs can modify verbs, adjectives , clauses, sentences, and other adverbs....

 indicating direction

Direction (geometry, geography)

Direction is the information contained in the relative position of one point with respect to another point without the distance information. Directions may be either relative to some indicated reference , or absolute according to some previously agreed upon frame of reference Direction is the...

 or geography

Geography

Geography is the science that studies the lands, features, inhabitants, and phenomena of Earth. A literal translation would be "to describe or write about the Earth". The first person to use the word "geography" was Eratosthenes...

.
East is one of the four cardinal directions or compass

Compass

A compass is a navigational instrument that shows directions in a frame of reference that is stationary relative to the surface of the earth. The frame of reference defines the four cardinal directions – north, south, east, and west. Intermediate directions are also defined...

 points. It is the opposite of west

West

West is a noun, adjective, or adverb indicating direction or geography.West is one of the four cardinal directions or compass points. It is the opposite of east and is perpendicular to north and south.By convention, the left side of a map is west....

 and is perpendicular

Perpendicular

In geometry, two lines or planes are considered perpendicular to each other if they form congruent adjacent angles . The term may be used as a noun or adjective...

 to north

North

North is a noun, adjective, or adverb indicating direction or geography.North is one of the four cardinal directions or compass points. It is the opposite of south and is perpendicular to east and west.By convention, the top side of a map is north....

 and south

South

South is a noun, adjective, or adverb indicating direction or geography.South is one of the four cardinal directions or compass points. It is the opposite of north and is perpendicular to east and west.By convention, the bottom side of a map is south....

.

By convention

Norm (sociology)

Social norms are the accepted behaviors within a society or group. This sociological and social psychological term has been defined as "the rules that a group uses for appropriate and inappropriate values, beliefs, attitudes and behaviors. These rules may be explicit or implicit...

, the right side of a map

Map

A map is a visual representation of an area—a symbolic depiction highlighting relationships between elements of that space such as objects, regions, and themes....

 is east.

To go east using a compass for navigation

Navigation

Navigation is the process of monitoring and controlling the movement of a craft or vehicle from one place to another. It is also the term of art used for the specialized knowledge used by navigators to perform navigation tasks...

, set a bearing

Bearing (navigation)

In marine navigation, a bearing is the direction one object is from another object, usually, the direction of an object from one's own vessel. In aircraft navigation, a bearing is the actual compass direction of the forward course of the aircraft...

 or azimuth of 90°.

East is the direction toward which the Earth

Earth

Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...

 rotates about its axis, and therefore the general direction from which the Sun

Sun

The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...

 appears to rise.

During the Cold War

Cold War

The Cold War was the continuing state from roughly 1946 to 1991 of political conflict, military tension, proxy wars, and economic competition between the Communist World—primarily the Soviet Union and its satellite states and allies—and the powers of the Western world, primarily the United States...

, "The East" was sometimes used to refer to the Warsaw Pact

Warsaw Pact

The Warsaw Treaty Organization of Friendship, Cooperation, and Mutual Assistance , or more commonly referred to as the Warsaw Pact, was a mutual defense treaty subscribed to by eight communist states in Eastern Europe...

 and Communist China

People's Republic of China

China , officially the People's Republic of China , is the most populous country in the world, with over 1.3 billion citizens. Located in East Asia, the country covers approximately 9.6 million square kilometres...

, along with other Communist nations.

Throughout history, the East has also been used by Europeans in reference to the Orient

Orient

The Orient means "the East." It is a traditional designation for anything that belongs to the Eastern world or the Far East, in relation to Europe. In English it is a metonym that means various parts of Asia.- Derivation :...

 and Asia

Asia

Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...

n societies.

Etymology

The word east is derived from the Proto-Germanic *aus-to- or *austra- "east, toward the sunrise" , from PIE *aus- "to shine," or "dawn". Ēostre

Eostre

Old English Ēostre and Old High German Ôstarâ are the names of a Germanic goddess whose Anglo-Saxon month, Ēostur-monath , has given its name to the festival of Easter...

, a Germanic goddess of dawn, might have been a personification of both dawn and the cardinal points.