/ Dictionary / Index I imp. gal.: Meaning and Definition of Find definitions for: imp. gal. Pronunciation: [key] imperial gallon. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. impf. Imphal Related Content Daily Word Quiz: spectral Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language