- a device for controlling the passage of fluid or air through a pipe, duct, etc., especially an automatic device allowing movement in one direction only；short for thermionic valve
noun: valve, plural noun: valves
- 1. a device for controlling the passage of fluid or air through a pipe, duct, etc., especially an automatic device allowing movement in one direction only a valve shuts off the flow from the boiler when the water is hot enough
- ▪ British short for thermionic valve
- ▪ a cylindrical mechanism in a brass instrument which, when depressed or turned, admits air into different sections of tubing and so extends the range of available notes.
- ▪ a membranous fold in a hollow organ or tubular structure, such as a blood vessel or the digestive tract, which maintains the flow of the contents in one direction by closing in response to any pressure from reverse flow the aortic valve
- 2. each of the halves of the hinged shell of a bivalve mollusc or brachiopod, or of the parts of the compound shell of a barnacle.
- ▪ each of the halves or sections into which a dry fruit (especially a pod or capsule) dehisces.