/ Dictionary / Index F felsite: Meaning and Definition of Find definitions for: fel•site Pronunciation: (fel'sīt), [key] — n. a dense, fine-grained, igneous rock consisting typically of feldspar and quartz, both of which may appear as phenocrysts. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. felsic felspar Related Content Daily Word Quiz: vertigo Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language