Thesaurus

noun, plural thesauruses, thesauri
[-sawr-ahy] /-ˈsɔr aɪ/ (Show IPA)
1.
a dictionary of synonyms and antonyms, such as the online Thesaurus.com.
2.
any dictionary, encyclopedia, or other comprehensive reference book.
3.
a storehouse, repository, or treasury.
4.
Computers.

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.
a dictionary of synonyms and antonyms stored in memory for use in word processing.

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 Thesaurus.com, 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.
noun (pl) -ruses, -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