The mechanical system that operates the valves in an internal combustion engine.

A mechanism in a diving regulator which controls the supply of gas by opening to provide flow when the user inhales, and shuts off supply when inhalation stops.

(chiefly historical) An electronic device incorporating electrons from a glowing cathode inside an evacuated glass tube, functioning as a switch, amplifier etc.

(in an internal combustion engine) a valve through which the products of combustion escape from the cylinder to the manifold

A liquid used to lubricate valves in brass instruments.

(mechanics) A valve (as in an internal combustion engine) which consists of a sliding shaft with a disk on the end (the disk being shaped to alternately plug and unplug a matching port) and which is operated by springs and possibly cams interacting with the shaft.

A heart valve with three cusps which prevents backflow of blood from the right ventricle into the right atrium.

A type of valve having a small orifice and a needle-like plunger, allowing precise regulation of generally small flow rates.

A valve that may be turned to regulate the flow of fluid through a pipe (especially water through a mains supply)

(anatomy) The mitral valve.