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