East is most commonly a noun, adjective, or adverb indicating direction or geography.
East is the direction from which the sun rises at the equinox. It is one of the four cardinal points of the compass, upon which it is considered the opposite of West, and at right angles to North and South.
"The East" also often refers to Eastern countries. When used in this sense, it could, depending on context, refer to the Middle East, Eastern Europe, South Asia, East Asia, or even all of Asia. This meaning of the word merges with the concept of Eastern society.