/ Dictionary / Index G GCI: Meaning and Definition of Find definitions for: GCI Pronunciation: [key] — Mil. Mil. ground-controlled interception. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. G.C.F. G clef Related Content Daily Word Quiz: neologism Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language