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thesaurus Line breaks: the|saurus
Pronunciation: /θɪˈsɔːrəs/

Definition of thesaurus in English:

noun (plural thesauri θɪˈsɔːrʌɪ or thesauruses)

1A book that lists words in groups of synonyms and related concepts.
Example sentences
  • The thesaurus provides synonyms, antonyms and related words, and is accessed by just right-clicking on the word to be looked up, and selecting ‘Thesaurus’ from the menu.
  • Use your word processor's thesaurus to find synonyms for ‘said’ and use them to convey a speaker's frame of mind or actions to the reader.
  • Unlike a conventional thesaurus, this book concentrates on word groups, and not on individual words.
wordfinder, wordbook, synonym dictionary/lexicon
rare synonymy
1.1 archaic A dictionary or encyclopedia.


Late 16th century: via Latin from Greek thēsauros 'storehouse, treasure'. The original sense 'dictionary or encyclopedia' was narrowed to the current meaning by the publication of Roget's Thesaurus of English Words and Phrases (1852).

  • The source of thesaurus is Greek thēsauros ‘storehouse, treasure’. In the late 16th century a thesaurus was a dictionary or encyclopedia; the current English meaning of the word comes from the title of one of the best-known works of reference, Roget's Thesaurus of English Words and Phrases, first published in 1852.

Words that rhyme with thesaurus

brachiosaurus, brontosaurus, canorous, chorus, Epidaurus, giganotosaurus, Horus, megalosaurus, pelorus, porous, sorus, stegosaurus, Taurus, torus, tyrannosaurus

Definition of thesaurus in:

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