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’
    • ‘On offer is a 3 litre petrol engine V6 with four valves per cylinder.’
    • ‘Such valves allow the intake of air but not the outflow.’
    • ‘For example, every fixture must include an isolation valve to allow maintenance personnel to shut down individual fixtures.’
    • ‘The patented sensitive microphone detects the noise of a water leak transmitted along pipes, valves, and hydrants and through the ground.’
    • ‘If automatic valves are used, they should be controlled from a central location and be easy to override with manual controls.’
    • ‘The system is regulated by a height control valve which allows fluid to move between spheres to keep the car level.’
    • ‘The main tanks were fitted with simultaneously opening dump valves controlled by either pilot.’
    • ‘Multifunctional tools, such as graders, require an electrical outlet and switches on the loader to control hydraulic diverter valves.’
    • ‘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.’
    • ‘Its speed can be influenced by the waste-gate valve, which is controlled by the pressure-driven converter.’
    • ‘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.’
    • ‘One of the safety shutoff valves had closed in the coolant system of the third engine.’
    • ‘Using them would mean that attachments could be installed without disassembly of the main control valve or draining of hydraulic fluids.’
    • ‘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 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.’
    • ‘All control valves are located on the left side of the machine for convenience.’
    • ‘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.’
    • ‘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 pipelines are controlled by computer systems, linked to sensors and automatic valves to manage the speed of flow.’
    vent, vent hole, way out, exit, egress
    View synonyms
    1. 1.1Electronics
      British term for thermionic tube
      • ‘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.’
      • ‘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.’
    2. 1.2Music A cylindrical mechanism in a brass instrument that, when depressed or turned, admits air into different sections of tubing and so extends the range of available notes.
      • ‘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.’
    3. 1.3Anatomy Zoology A membranous fold in a hollow organ or tubular structure, such as a blood vessel or the digestive tract, that maintains the flow of the contents in one direction by closing in response to any pressure from reverse flow.
      • ‘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.’
      • ‘If the heart valves can't open and close correctly, blood can't flow smoothly.’
      • ‘During pregnancy, hormones relax the muscles in your digestive tract, including the valve in the esophagus.’
    4. 1.4Zoology Each of the halves of the hinged shell of a bivalve mollusk 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.’
      • ‘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.’
      • ‘Note that each shell valve is symmetrical about the midline, but the two shell valves are often unequal in size.’
    5. 1.5Botany Each of the halves or sections into which a dry fruit (especially a pod or capsule) dehisces.
      • ‘The fruit is a small oblong capsule with two valves containing many small seeds.’
      • ‘Dehiscence of the anther valves begins at the distal end.’
      • ‘Fruits were harvested just prior to dehiscence of the capsule valves.’
      • ‘The brush-like hairs at the end of the anther tube are not bent, and they enclose the valve.’
      • ‘As the pollinator pushes back the brush-like hairs, the valve opens releasing the pollen onto the back of the pollinator.’


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