Definition of valve in English:



  • 1A 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’
    • ‘The system is regulated by a height control valve which allows fluid to move between spheres to keep the car level.’
    • ‘One of the safety shutoff valves had closed in the coolant system of the third engine.’
    • ‘For example, every fixture must include an isolation valve to allow maintenance personnel to shut down individual fixtures.’
    • ‘If the burner doesn't ignite quickly, shut off the valves, leave the lid open and allow the grill to air out for several minutes before you try to light it again.’
    • ‘The required ingredients are then pumped from their storage areas through a series of valves and pipes that eventually lead to the blend tanks.’
    • ‘The main tanks were fitted with simultaneously opening dump valves controlled by either pilot.’
    • ‘The pump design accomplishes all fluid control functions while eliminating valves that can clog, fatigue, and fail, causing accuracy drifting and pump failure over time.’
    • ‘The patented sensitive microphone detects the noise of a water leak transmitted along pipes, valves, and hydrants and through the ground.’
    • ‘Multifunctional tools, such as graders, require an electrical outlet and switches on the loader to control hydraulic diverter valves.’
    • ‘The pipelines are controlled by computer systems, linked to sensors and automatic valves to manage the speed of flow.’
    • ‘On offer is a 3 litre petrol engine V6 with four valves per cylinder.’
    • ‘All control valves are located on the left side of the machine for convenience.’
    • ‘If you choose to have a fountain in your water garden, place the control valve from the fountain assembly onto the top outlet of the pump.’
    • ‘The main type of central heating system is wet - where hot water is circulated through pipes and goes to radiators with valves that control the amount of time it spends there.’
    • ‘If automatic valves are used, they should be controlled from a central location and be easy to override with manual controls.’
    • ‘Such valves allow the intake of air but not the outflow.’
    • ‘Its speed can be influenced by the waste-gate valve, which is controlled by the pressure-driven converter.’
    • ‘To remove the clog, close the shutoff valve at the bottom of the radiator and unscrew the air vent.’
    • ‘Close the water valves and disconnect the water lines just above the valves and the drain piping at the trap.’
    • ‘Using them would mean that attachments could be installed without disassembly of the main control valve or draining of hydraulic fluids.’
    vent, vent hole, way out, exit, egress
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    1. 1.1British
      • ‘Equipped with transistors instead of valves, it could be operated for 80 hours on four hearing aid batteries, costing 2s 6d each.’
      • ‘Unlike delicate solid-state circuitry, valves are incredibly robust from an electrical perspective.’
      • ‘You could even build a functional, if somewhat cumbersome, guitar amplifier with a hydraulic system replacing transistors or valves.’
      • ‘Electronic valves are no longer used and have been replaced by transistors and diodes which have a low current consumption, greater reliability and much smaller dimensions.’
      • ‘Silicon chips transformed the then slowly evolving world of electrical circuits and valves to the vibrant and fast developing world of electronics.’
    2. 1.2Music 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.
      • ‘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.’
      • ‘The later introduction of valves extended the versatility of brass instruments to cover the full chromatic scale.’
    3. 1.3Anatomy 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’
      • ‘Veins become varicose when valves in the veins closest to the skin's surface don't function correctly.’
      • ‘When crocodiles are completely submerged, the ears and nostrils are closed by valves, and the eyes covered by membranes.’
      • ‘The condition results from problems with valves in the veins of the leg.’
      • ‘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.’
  • 2Zoology
    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.

    • ‘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.’
    • ‘The remains usually consisted of a large piece of one valve plus a fragment of the other valve attached by a virtually intact hinge.’
    • ‘All these plates that attach to the floor of the brachial valve may have been thickened by secondary overgrowth.’
    1. 2.1Botany Each of the halves or sections into which a dry fruit (especially a pod or capsule) dehisces.
      • ‘As the pollinator pushes back the brush-like hairs, the valve opens releasing the pollen onto the back of the pollinator.’
      • ‘The fruit is a small oblong capsule with two valves containing many small seeds.’
      • ‘Dehiscence of the anther valves begins at the distal end.’
      • ‘The brush-like hairs at the end of the anther tube are not bent, and they enclose the valve.’
      • ‘Fruits were harvested just prior to dehiscence of the capsule valves.’


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