Looking for synonyms or antonyms? Try the Merriam-Webster Thesaurus.

thesaurus

noun

the·sau·rus | \ thi-ˈsȯr-əs

plural thesauri\ thi-ˈsȯr-ˌī ,

-ˌē \ or thesauruses\ thi-ˈsȯr-ə-səz

Definition of thesaurus

1a : a book of words or of information about a particular field or set of concepts especially : a book of words and their synonyms

b : a list of subject headings or descriptors usually with a cross-reference system for use in the organization of a collection of documents for reference and retrieval

2 : treasury, storehouse

Other Words from thesaurus Did You Know? Example Sentences Learn More about thesaurus

Keep scrolling for more

Did You Know?

In the early 19th century, archaeologists borrowed the Latin word thesaurus to denote an ancient treasury, such as that of a temple. Soon after, the word was metaphorically applied to a book containing a "treasury" of words or information about a particular field. In 1852, the English scholar Peter Mark Roget published his Thesaurus of English Words and Phrases, in which he listed a treasury of related words organized into numerous categories. This work led to the common acceptance of the term "thesaurus" for "a book of words and their synonyms." Finally, during the 1950s, "thesaurus" began being used in the field of word processing to refer to a list of related terms used for indexing and retrieval.

Examples of thesaurus in a Sentence

Recent Examples on the Web

Pack a low-back chair and a picnic (and maybe a thesaurus), and skip merrily off into the forest with Theseus and Hippolyta. — Brittany Martin, Los Angeles Magazine, "The 7 Best Things to Do in L.A. This Weekend," 27 June 2018 Be your own thesaurus and fact-checker, and squint with your ears at phrasing that comes off as aggressively neutral. — Michael Andor Brodeur, BostonGlobe.com, "The official language of the US? It’s euphemism.," 21 June 2018 Regular viewers of White House press briefings are familiar with Newsmax's John Gizzi, a human thesaurus with a deep voice and deliberate style of questioning that stands out in a frenzied room. — Callum Borchers, Washington Post, "Would Bill O’Reilly’s viewers follow him to a smaller network?," 16 May 2018 The physicians who inspected the twins included Dr. Peter Mark Roget, compiler of his eponymous thesaurus. — Vanessa Hua, San Francisco Chronicle, "‘Inseparable,’ by Yunte Huang," 10 May 2018 From ThinkProgress: The first five vendors combined offered just five romance novels, 14 religious texts, 24 drawing or coloring books, 21 puzzle books, 11 how-to books, one dictionary and one thesaurus. — Monique Judge, The Root, "New York Department of Corrections Puts Severe Restrictions on Books Prisoners Can Receive," 8 Jan. 2018 No thesaurus on earth can provide the appropriate adjectives. — Matt Calkins, The Seattle Times, "At least none of the Seahawks tried to hide the fact of just how awful they played Sunday," 17 Dec. 2017 Or perhaps his anti-Trump, pro-Clinton sentiments were not germane to his mere copy editing or his reliance on a thesaurus. — Victor Davis Hanson, National Review, "One Mueller-Investigation Coincidence Too Many," 12 Dec. 2017 At the same time, the movie’s presumably normally gifted men are as superfluous to the proceedings as a thesaurus in the writers’ room. — Jeannette Catsoulis, New York Times, "Review: Bad Grandmoms Show Up for ‘A Bad Moms Christmas’," 2 Nov. 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'thesaurus.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.