/ Dictionary / Index G gph: Meaning and Definition of Find definitions for: gph Pronunciation: [key] gallons per hour. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. gpd gpm 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