/ Dictionary / Index H half-gallon: Meaning and Definition of Find definitions for: half-gal•lon Pronunciation: (haf'gal'un, häf'-), [key] — n. a half of a gallon, equal to 2 quarts (1.9 liters). —adj. holding or consisting of two quarts. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. half gainer half-glasses Related Content Daily Word Quiz: cygnet Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language