/ Dictionary / Index D differential gear: Meaning and Definition of Find definitions for: dif'feren'tial gear' Pronunciation: [key] — Mach. Mach. differential (def. 7). any of various comparable arrangements of gears, as an epicyclic train. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. differential equation differential geometry 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