/ Dictionary / Index G GySgt: Meaning and Definition of Find definitions for: GySgt Pronunciation: [key] — Marine Corps. Marine Corps. gunnery sergeant. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. gyrus gyttja Related Content Daily Word Quiz: fabricate Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language