/ Dictionary / Index S siderite: Meaning and Definition of Find definitions for: sid•er•ite Pronunciation: (sid'u-rīt"), [key] — n. Also calleda common mineral, iron carbonate, FeCO, usually occurring in yellowish to deep-brown cleavable masses: a minor ore of iron. a meteorite consisting almost entirely of metallic minerals. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: siderite (Thesaurus) sidereal year sidero- Related Content Daily Word Quiz: acquiesce Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language