thesaurus

noun3

1. •
   A publication that provides synonyms (and sometimes antonyms and other semantic relations) for the words of a given language.

   • "Roget" is the leading brand name for a print English thesaurus that lists words under general concepts rather than just close synonyms.
2. •
   A hierarchy of subject headings: canonical titles of themes and topics, the titles serving as search keys.
3. •
   (no longer used) A dictionary or encyclopedia.