lexicon Meaning, Definition & Usage

  1. noun a language user's knowledge of words
    mental lexicon; vocabulary.
  2. noun a reference book containing an alphabetical list of words with information about them
    dictionary.

WordNet

Lex"i*con noun
Etymology
Gr. (sc.), neut. of of or belonging to words, fr. a speaking, speech, a way of speaking, a single word or phrase, fr. to say, to speak. See Legend.
Definitions
  1. A vocabulary, or book containing an alphabetical arrangement of the words in a language or of a considerable number of them, with the definition of each; a dictionary; especially, a dictionary of the Greek, Hebrew, or Latin language. also, a dictionary for use in computational linguistics

Webster 1913