/ Dictionary / Index G gm.: Meaning and Definition of Find definitions for: gm. Pronunciation: [key] gram; grams. G.M. Pronunciation: [key] General Manager. Grand Marshal. Grand Master. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: gm (Thesaurus) glyptography G-man 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