(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

(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 liquid used to lubricate valves in brass instruments.

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

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

An automatic non-return valve that opens when the boiler is at less than atmospheric pressure so as to avoid any risk of vacuum collapse when a hot boiler is allowed to cool down out of service.

plural of vacuum valve

plural of suction valve