/ Dictionary / Index G G.C.F.: Meaning and Definition of Find definitions for: G.C.F. Pronunciation: [key] greatest common factor. See Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. GCE GCI Related Content Daily Word Quiz: eureka Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language