/ Dictionary / Index X xanthin: Meaning and Definition of Find definitions for: xan•thin Pronunciation: (zan'thin), [key] — n. the part of the coloring matter in yellow flowers that is insoluble in water. Cf. a yellow coloring matter in madder. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. xanthic acid xanthine Related Content Daily Word Quiz: soporific Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language