camshaft
/ˈkæmʃæft/
noun
- A rotating shaft in an engine that controls the opening and closing of the valves.
- A camshaft has lobes that push the valves open at the right time.
- The mechanic replaced the worn camshaft to restore the engine's performance.
- In a car engine, the camshaft is driven by the crankshaft via a timing belt.