[thi-sawr-uh s]
See more synonyms for thesaurus on
noun, plural the·sau·rus·es, the·sau·ri [-sawr-ahy] /-ˈsɔr aɪ/.
  1. a dictionary of synonyms and antonyms, such as the online
  2. any dictionary, encyclopedia, or other comprehensive reference book.
  3. a storehouse, repository, or treasury.
  4. Computers.
    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’

online thesaurus

noun, plural online thesauruses, online thesauri.
  1. 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. 2018

Related Words for thesaurus

glossary, lexicon, terminology, vocabulary, onomasticon

Examples from the Web for thesaurus

Contemporary Examples of thesaurus

Historical Examples of thesaurus

  • Most of these (along with Tatian), are to be found in Schilter's Thesaurus.

  • And now Pabo distinctly remembered that the Thesaurus was not far beyond it.

    Pabo, The Priest

    Sabine Baring-Gould

  • You couldn't trust this Swede as far as you could throw a thesaurus by the tail.

    Yellowstone Nights

    Herbert Quick

  • Then I wrote at the top of the paper, 'Thesaurus for the Ennuied.'


    George Madden Martin

  • First of all his age is thirty-six, and he is the editor of The Thesaurus.

    'I Believe' and other essays

    Cyril Arthur Edward Ranger Gull

British Dictionary definitions for thesaurus


noun plural -ruses or -ri (-raɪ)
  1. a book containing systematized lists of synonyms and related words
  2. a dictionary of selected words or topics
  3. 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

Word Origin and History for thesaurus

1823, "treasury, storehouse," from Latin thesaurus "treasury, treasure," from Greek thesauros "a treasure, treasury, storehouse, chest," from root of tithenai "to put, to place." The meaning "encyclopedia filled with information" is from 1840, but existed earlier as thesaurarie (1590s), used as a title by early dictionary compilers. Meaning "collection of words arranged according to sense" is first attested 1852 in Roget's title. Thesaur is attested in Middle English with the meaning "treasure" (15c.-16c.).

Online Etymology Dictionary, © 2010 Douglas Harper