The term 'lexicon' refers to a collection of words and phrases used in a particular LANGUAGE or field of study. The crossword solutions for this term include 'WORDBOOK' (8 letters), 'THESAURUS' (9 letters), 'DICTIONARY' (10 letters), 'JARGON' (6 letters), 'LANGUAGE' (8 letters), 'VOCABULARY' (10 letters), and 'TOME' (4 letters). A WORDBOOK is a book containing a list of words, often with definitions. A THESAURUS is a book of synonyms and antonyms. A DICTIONARY is a book that lists words in alphabetical order and provides their definitions. JARGON is specialized LANGUAGE used by a particular group or profession. LANGUAGE is a system of communication using words, either spoken or written. VOCABULARY is a set of words used in a particular LANGUAGE. Finally, a TOME is a large book, usually one that is scholarly or technical in nature.