Lexicon may refer to one of several things:

• A lexicon, a list of words together with additional word-specific information, i.e., a dictionary. In the lexicon of a language, lexical words or nouns refer to things.
• In mathematics, lexicons are real numbers with particular properties.

• Lexicon, a text editor and word processor MS-DOS program that was extremely popular in the Soviet Union and Russia at the end of 1980s and in 1990s.

• Lexicon, a role-playing game using the Wiki software.

• Lexicon, a manufacturer of various audio/video components and music production equipment.

• Lexical analysis, the name given to the processing of an input sequence of input to produce, as output, a sequence of symbols called "lexical tokens".