Definition of valve in English:

valve

Line breaks: valve
Pronunciation: /valv
 
/

noun

1A device for controlling the passage of fluid through a pipe or duct, 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
More example sentences
  • The system is regulated by a height control valve which allows fluid to move between spheres to keep the car level.
  • Its speed can be influenced by the waste-gate valve, which is controlled by the pressure-driven converter.
  • Multifunctional tools, such as graders, require an electrical outlet and switches on the loader to control hydraulic diverter valves.
1.1British short for thermionic valve.
More example sentences
  • You could even build a functional, if somewhat cumbersome, guitar amplifier with a hydraulic system replacing transistors or valves.
  • Equipped with transistors instead of valves, it could be operated for 80 hours on four hearing aid batteries, costing 2s 6d each.
  • Silicon chips transformed the then slowly evolving world of electrical circuits and valves to the vibrant and fast developing world of electronics.
1.2 Music 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.
More example sentences
  • The later introduction of valves extended the versatility of brass instruments to cover the full chromatic scale.
  • For trumpeters the left hand acts merely as a clamp holding the instrument whilst the three valves are operated by fingers of the right hand.
  • The soloists played on natural horns, instruments that have no valves and are not as powerful as their modern descendants.
1.3 Anatomy & Zoology 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
More example sentences
  • When crocodiles are completely submerged, the ears and nostrils are closed by valves, and the eyes covered by membranes.
  • During pregnancy, hormones relax the muscles in your digestive tract, including the valve in the esophagus.
  • If the heart valves can't open and close correctly, blood can't flow smoothly.
2 Zoology 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.
More example sentences
  • The brachiopods from the limestone unit are mostly preserved as shells, most with valves conjoined.
  • The two shell valves would have been rigidly fixed in place, and the dorsal margin could not have been more than a poorly elastic structure, if that.
  • Note that each shell valve is symmetrical about the midline, but the two shell valves are often unequal in size.
2.1 Botany Each of the halves or sections into which a dry fruit (especially a pod or capsule) dehisces.
More example sentences
  • Fruits were harvested just prior to dehiscence of the capsule valves.
  • Dehiscence of the anther valves begins at the distal end.
  • The fruit is a small oblong capsule with two valves containing many small seeds.

Origin

late Middle English (denoting a leaf of a folding or double door): from Latin valva.

Derivatives

valved

adjective
[in combination]: a branchiopod has a two-valved outer covering

valveless

adjective
More example sentences
  • It is equipped with a patented four-stroke valveless engine and automatic transmission.
  • Being a valveless instrument, the Alphorn produces only those pitches that occur in the natural overtone or harmonic series.
  • The low cardiac output manifests as fatigue, while the higher end diastolic pressure is transmitted backwards through the valveless pulmonary veins to the pulmonary capillaries, resulting in exertional dyspnoea.

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