[ thi-sawr-uh s ]
/ θɪˈsɔr əs /

noun, plural the·sau·rus·es, the·sau·ri [-sawr-ahy] /-ˈsɔr aɪ/.

a dictionary of synonyms and antonyms, such as the online
any dictionary, encyclopedia, or other comprehensive reference book.
a storehouse, repository, or treasury.
  1. an index to information stored in a computer, consisting of a comprehensive list of subjects concerning which information may be retrieved by using the proper key terms.
  2. a dictionary of synonyms and antonyms stored in memory for use in word processing.

Origin of thesaurus

1730–40; < Latin thēsaurus < Greek thēsaurós ‘treasure, treasury’

Definition for thesaurus (2 of 2)

online thesaurus

noun, plural online thesauruses, online thesauri.

a thesaurus or dictionary of words with the same or nearly the same meanings, or synonyms, and their opposites, or antonyms, such as, available on the Internet or the World Wide Web, accessed through a web browser, and used by entering a query term into a search box on the site. An online thesaurus provides immediate electronic access to lists of alternate terms for the queried word, covering its various shades of meaning: This online thesaurus showed me that smart, as an adjective, not only means intelligent, but also stylish, or lively, and gave long lists of other words for each meaning. Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020

Examples from the Web for thesaurus

British Dictionary definitions for thesaurus

/ (θɪˈsɔːrəs) /

noun plural -ruses or -ri (-raɪ)

a book containing systematized lists of synonyms and related words
a dictionary of selected words or topics
rare a treasury

Word Origin for thesaurus

C18: from Latin, Greek: treasure
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012