/ Dictionary / Index X xanthosiderite: Meaning and Definition of Find definitions for: xan•tho•sid•er•ite Pronunciation: (zan"thu-sid'u-rīt"), [key] — n. a mineral, hydrous iron oxide, FeO&multiplydot;2HO. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. xanthophyll xanthous Related Content Daily Word Quiz: profiterole Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language