or gear box
a transmission, as in an automobile.
a shield or housing for gears.
Origin of gearbox
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
the metal casing within which a train of gears is sealed
this metal casing and its contents, esp in a motor vehicle
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