gearwheel
/ˈɡɪrˌwil/
noun
- A wheel with teeth around its edge that fits into another similar wheel to change the speed or direction of movement in a machine.
- The mechanic replaced the broken gearwheel in the clock.
- Each gearwheel in the bicycle chain helps the rider pedal more efficiently.
- The factory machine uses a large metal gearwheel to turn the conveyor belt.