Other forms: thesauri
A thesaurus is a book grouping words by their meanings. Look it up in a thesaurus.
It is not a dictionary of synonyms, since it groups related ideas rather than exact equivalents. A thesaurus used without judgement produces writing that sounds translated.
1nounthesaurusA book grouping words by their meanings.
“The thesaurus offered eleven words and not one of them fitted.”
thesaurus is a book.
Latin thesaurus comes from Greek thesauros, a storehouse or treasure.
Ancient Greek
θησαυρός — storehouse, treasure
Latin
thēsaurus
English, today
thesaurus
16th century, Latin thēsaurus, from Ancient Greek θησαυρός (“storehouse, treasure”); its current English usage/meaning was established soon after the publication of Peter Roget's Thesaurus of English Words and Phrases in 1852. a doublet of treasure.
Etymology from Wiktionary, CC BY-SA