thesaurus

plural thesauri · plural thesauruses

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.

   1 more example

   As reference books go, the thesaurus has had a somewhat checkered history, in fact, and has probably occasioned as much bad writing as good.

   2008 April 18, Charles Mcgrath, “The Keeper (See: Steward, Caretaker) of Synonyms”, in New York Times

   Synonyms: synonymicon, wordhoard

2. archaicA dictionary or encyclopedia.
3. computingA hierarchy of subject headings: canonical titles of themes and topics, the titles serving as search keys.