[ thi-sawr-uhs ]
/ θɪˈsɔr əs /
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noun, plural the·sau·rus·es, the·sau·ri [-sawr-ahy]. /-ˈsɔr aɪ/.
a dictionary of synonyms and antonyms, such as the online Thesaurus.com.
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.
In effect, this quiz will prove whether or not you have the skills to know the difference between “affect” and “effect.”
Question 1 of 7
The rainy weather could not ________ my elated spirits on my graduation day.
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Origin of thesaurus

First recorded in 1730–40; from Latin thēsaurus, from Greek thēsaurós “treasure, treasury”
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2022

How to use thesaurus in a sentence

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