Clutch

A clutch is a subcomponent of an engine's transmission designed to allow engagement or disengagement of the engine to whatever apparatus is being driven. There are many different clutch designs, but most are based on locking plates, where the plates are tightly held together when the clutch is engaged, but held less tightly and allowed to slip over each other when the clutch is disengaged.

1. Dry clutch
2. Wet clutch

See also fan clutch[?]