Dictionary.com
definitions

differential gear

noun Machinery.
  1. differential(def 7).
  2. any of various comparable arrangements of gears, as an epicyclic train.

Origin of differential gear

First recorded in 1885–90
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
British Dictionary definitions for differential gear

differential gear

noun
  1. the epicyclic gear mounted in the driving axle of a road vehicle that permits one driving wheel to rotate faster than the other, as when cornering
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012