/ Dictionary / Index D diff.: Meaning and Definition of Find definitions for: diff. Pronunciation: [key] difference. different. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. dif diffeomorphism Related Content Daily Word Quiz: agitated Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language