DictionarygearMotion transmission
noun

gear

A mechanical arrangement that transmits motion and controls speed.

A low gear helps the truck climb the steep hill.

Etymology

The older word names equipment or outfitting. The mechanical sense specialized that equipment to the connected parts that transmit motion and determine speed.

More examples

  • She shifts into second gear as the car gains speed.
  • The motor drives the rollers through a reduction gear.
  • This bicycle has enough gears for hills and flat roads.

Forms

gear · gears

gearbox noun — A housing containing gears that transmit power.

gearshift noun — A control used to change vehicle gears.

Similar words

gearing
Refers to a system of gears, not one speed setting.
transmission
Names the larger system that transfers power in a vehicle.