lexicon

The word lexicon has a number of closely-related meanings, which can easily lead to confusion and may cause the word to be used in an awkward way. Lexicon can refer to a general dictionary of a language (as in "a lexicon of the Hebrew language") and also to a narrower printed compilation of words within some sphere (as in "a medical lexicon" or "a lexicon of the German in Finnegans Wake").

Similarly, lexicon can refer both to the vocabulary of a specific group of people ("the lexicon of French") or to the general language used by an unspecified group of people ("a word that has not entered the general lexicon yet"). It may also often be found in reference to the vocabulary employed by a particular speaker ("'Failure' is not a word in my lexicon").