A Lexicon

1. The vocabulary of a language.Synonyms: word-hoard, word-stock
2. (linguistics) A dictionary that includes or focuses on lexemes.Synonym: wordbook Lexicon - Wikipedia
3. A dictionary of Classical Greek, Hebrew, Latin, or Aramaic.
4. (programming) The lexicology of a programming language. (Usually called lexical structure.)
5. (rare) Any dictionary.
6. The vocabulary used by or known to an individual. (Also called lexical knowledge)
7. A vocabulary specific to a certain subject.