/ Dictionary / Index X xanthine: Meaning and Definition of Find definitions for: xan•thine Pronunciation: (zan'thēn, -thin), [key] — n. Biochem., Chem. a crystalline, nitrogenous compound, CHNO, related to uric acid, occurring in urine, blood, and certain animal and vegetable tissues. any derivative of this compound. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: xanthine (Thesaurus) xanthin Xanthippe Related Content Daily Word Quiz: diligent Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language