/ Dictionary / Index G gpm: Meaning and Definition of Find definitions for: gpm Pronunciation: [key] gallons per minute. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. gph G.P.O. Related Content Daily Word Quiz: procrastinate Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language