Breadcrumb Home > Dictionary > Index H hydantoin: Meaning and Definition of Find definitions for: hy•dan•to•in Pronunciation: (hī-dan'tō-in), [key] — n. Pharm. a colorless, needlelike, crystalline compound, CHNO, used in the synthesis of pharmaceutical substances and resins. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: hydantoin (Thesaurus) hyd. hydathode TrendingHere are the facts and trivia that people are buzzing about. Biographies: Notable Jewish Religious Leaders Current Events This Week: September 2023 Hispanic Population and the 2010 U.S. Census Preamble of the United Nations Charter The Jewish Calendar ✖ Related Content Daily Word Quiz: qiviut Analogy of the Day: Today’s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language