A camshaft-driven valve in the cylinder head that opens to allow the fuel-air charge into the cylinder and closes to form part of the combustion chamber during the compression and power strokes.

The valve that opens to permit the fuel mixture into the cylinder. It closes during the compression and combustion strokes. Some engines have more than one intake valve to each cylinder. Also called the "inlet valve."

n: 1. the mechanism on an engine through which air and sometimes fuel are admitted to the cylinder. 2. on a mud pump, the valve that opens to allow mud to be drawn into the pump by the pistons moving in the liners.