<p><strong>Noun</strong></p><ul><li>A word having the same or nearly the same meaning as another word in the same language, as happy, joyful, elated.</li><li>A dictionary of synonyms and antonyms (or opposites), such as Thesaurus.com, is called a thesaurus.</li><li>A word or expression accepted as another name for something, as Arcadia for pastoral simplicity or Wall Street for U.S. financial markets; metonym.</li><li>In Biology, one of two or more scientific names applied to a single taxon.</li></ul>