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thesaurus

noun

the·​sau·​rus thi-ˈsȯr-əs 

plural thesauri thi-ˈsȯr-ˌī 

-ˌē

or thesauruses thi-ˈsȯr-ə-səz 

1

a

: 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

thesaural

thi-ˈsȯr-əl 

adjective

Did you know?

In the early 19th century, archaeologists borrowed the Latin word thesaurus to denote an ancient treasury, such as that in 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 semantically related words organized into numerous categories. This work led to the common acceptance of the term thesaurus to refer to "a book of words and their synonyms." The word developed another meaning in the 1950s, when thesaurus began being used in the field of word processing to refer to a list of related terms used for indexing and retrieval.

Example Sentences

Recent Examples on the Web

Accordingly, to try to describe the near $110 billion the US has pledged to Ukraine in the last year sends one scrambling for a thesaurus. —Thomas Sadoski, CNN, 2 Mar. 2023

The novels McCarthy published in 2022, at the age of 89, permanently resolve the question of whether McCarthy is a great novelist, or Louis L’Amour with a thesaurus. —Graeme Wood, The Atlantic, 5 Dec. 2022

So why does this paper seem to have been co-written by a thesaurus? —Neuroskeptic, Discover Magazine, 27 Jan. 2021

Joniak might need a thesaurus as Justin Fields’ career takes flight for the Bears. —Brad Biggs, Chicago Tribune, 7 Nov. 2022

After Jokic scorched the Spurs again in October for 32 points and 16 rebounds in a 102-96 Nuggets win in Denver, coach Gregg Popovich exhausted his thesaurus describing the 26-year-old’s greatness. —Jeff Mcdonald, San Antonio Express-News, 9 Dec. 2021

Over-the-top rhetoric that sounds as if someone locked Kiley in a room with a thesaurus, but doesn’t really conform to what even Newsom’s critics think of his performance. —Michael Hiltzik, Los Angeles Times, 15 Sep. 2021

Books, including a thesaurus so tattered from use that back when there were regular tours of the newsroom, the tour guide would show it to visitors. —Karina Bland, The Arizona Republic, 23 June 2021

Synonymy—the concept of distinct words signifying the same thing—was understood as far back as Ancient Greece, but the Archbishop of Seville authored the earliest work modern readers might recognize as a thesaurus. —Claudia Kalb, Smithsonian Magazine, 21 Apr. 2021

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Word History

Etymology

New Latin, from Latin, treasure, collection, from Greek thēsauros

First Known Use

circa 1823, in the meaning defined at sense 2

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Kids Definition

thesaurus

noun

the·​sau·​rus thi-ˈsȯr-əs 

plural thesauri -ˈsȯ(ə)r-ˌī 

-ˌē

or thesauruses -ˈsȯr-ə-səz 

: a book of words and their synonyms

Etymology

from scientific Latin thesaurus "treasury, storehouse, book of words," from Latin thesaurus "treasure, collection," from Greek thēsauros (same meaning) — related to treasure