Head definition1. The upper part of something.
2. A part of the engine which covers the piston and creates the combustion chamber . The proper name is cylinder head . See blown head gasket composite headlight , double-overhead cam exhaust header F-head engine , flathead gib-head key head gasket head restraint head tube heads up display headlight headliners headset headers high compression head , I-head engine , Jaguar Drophead L-head engine Lagonda Drophead overhead cam overhead valves Phillips head screw piston head sealed beam headlight T-head valve-in-head engine .