/ Dictionary / Index D differential rate: Meaning and Definition of Find definitions for: dif'feren'tial rate' Pronunciation: [key] a special lower rate, as one charged by one of two or more competing businesses. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. differential quotient differential topology Related Content Daily Word Quiz: gregarious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language