valve

American  

[valv] / vælv /

noun

• valves
  plural

1. any device for halting or controlling the flow of a liquid, gas, or other material through a passage, pipe, inlet, outlet, etc.

2. a hinged lid or other movable part that closes or modifies the passage in such a device.

3. Anatomy. a membranous fold or other structure that controls the flow of a fluid, as one that permits blood to flow in one direction only.

4. (in musical wind instruments of the trumpet class) a device for changing the length of the air column to alter the pitch of a tone.

5. Zoology.

   1. one of the two or more separable pieces composing certain shells.

   2. either half of the silicified shell of a diatom.

6. Botany.

   1. one of the segments into which a capsule dehisces.

   2. a flap or lidlike part of certain anthers.

7. Electronics (chiefly British). vacuum tube.

8. Archaic. one of the leaves of a double or folding door.

---

verb (used with object)

valved, valving

1. to provide with a means of controlling the flow of liquid, gas, etc., by inserting a valve.

valve British  

/ vælv /

noun

1. any device that shuts off, starts, regulates, or controls the flow of a fluid

2. anatomy a flaplike structure in a hollow organ, such as the heart, that controls the one-way passage of fluid through that organ

3. Also called: tube.   vacuum tube.  an evacuated electron tube containing a cathode, anode, and, usually, one or more additional control electrodes. When a positive potential is applied to the anode, electrons emitted from the cathode are attracted to the anode, constituting a flow of current which can be controlled by a voltage applied to the grid to produce amplification, oscillation, etc See also diode triode tetrode pentode

4. zoology any of the separable pieces that make up the shell of a mollusc

5. music a device on some brass instruments by which the effective length of the tube may be varied to enable a chromatic scale to be produced

6. botany

   1. any of the several parts that make up a dry dehiscent fruit, esp a capsule

   2. either of the two halves of a diatom cell wall

7. archaic a leaf of a double door or of a folding door

---

valve Scientific  

/ vălv /

1. 1. Any of various mechanical devices that control the flow of liquids, gases, or loose material through pipes or channels by blocking and uncovering openings.

   2. The movable part or element of such a device.

2. Any of various structures that prevent the backward flow of a body fluid, such as blood or lymph. Valves in the heart, veins, and lymphatic vessels contain flaps (known as cusps) that close in response to pressure created by the backflow of fluid.

3. One of the paired hinged shells of certain mollusks, such as clams and oysters.

4. See electron tube

---

Other Word Forms

Derived Forms

• undervalve
  noun
• valveless
  adjective
• valvelike
  adjective

Inflected Forms

Nouns

• valves
  plural

Etymology

Origin of valve

1350–1400; Middle English < Latin valvae leaves of a door

Explanation

A valve is a device that controls the flow of a liquid or gas. Before you fix the broken sink in your bathroom, you should turn the valve that shuts off the water. The simplest type of valve has a hinged flap allowing liquid to flow one direction, but blocking it from going the other way. This is called a "check valve." Anatomical valves — systems in your body that allow a flow of fluid, like the aortic valve near your heart — are structured very much the same way. The shells of mollusks like oysters and clams are also called valves. The word's earliest meaning was "one half of a folding door."

Example Sentences

See Examples For:

valve valves valved valving

An air valve had malfunctioned, according to the complaint, but Kettle refused to approve a fix afterwards because it would have led to train delays at Union Station.

From Los Angeles Times ● Sep. 15, 2026

A key pressure-release valve for global supply is also facing new threats.

From The Wall Street Journal ● Sep. 11, 2026

Engineers had to physically shut the valve because it was not responding to electrical control.

From BBC ● Sep. 8, 2026

Sealing off: Leronlimab blocks what's left of the virus from infecting immune cells -- the equivalent of sealing off the room with a water-tight valve.

From Science Daily ● Aug. 13, 2026

It seemed as though a valve had burst inside her and a great gush of energy was being released.

From "Matilda" by Roald Dahl

The same thing is happening at Iran’s land borders with Turkey, Turkmenistan and Afghanistan, dealing Tehran a self-inflicted blow and throttling trade through its few remaining economic release valves.

From The Wall Street Journal ● Sep. 17, 2026

He’d return with images of abandoned stairwells, dilapidated neon signage, Art Deco theater facades, boiler room control valves.

From Los Angeles Times ● Sep. 3, 2026

The strongest signal appeared in people whose mitral valves had already begun to degenerate.

From Science Daily ● Jul. 12, 2026

That means parents will have few relief valves to make the payments manageable.

From MarketWatch ● Jul. 1, 2026

The valves that lead to the trailer hoses are shut.

From "The Martian" by Andy Weir

Still today, the World Health Organization advises against using valved N95s.

From Slate ● May 20, 2022

"It was flushed into the drainage system that leads to an oil water separator that is valved off from the detention basin," Mura said.

From Salon ● Mar. 23, 2022

He immediately switched from the baritone horn, a valved instrument, to trombone.

From Washington Post ● May 11, 2021

Mr. Sax patented his family of valved brass instruments in 1846, as militarism was sweeping Europe.

From New York Times ● Nov. 6, 2015

He stood up, still chewing, put on his hieb, coat, and boots, and slipped otterlike out the self-sealing valved door.

From "The Left Hand of Darkness" by Ursula K. Le Guin

I have my own idea about what I want to do for a valving system.'

From Time Magazine Archive

This can be prevented by valving in hot air from the exhaust stacks.

From Time Magazine Archive

They first softened the primary piston, working a large amount on both the high and low speed compression valving in order to make the shock run a bit softer and have a much smoother action.

From Time Magazine Archive

Much weight is saved by better fuel tanks, pumps, valving, etc.

From Time Magazine Archive

Dean Moran, opposite, eyes clenched, lips valving open as a cobra slithers out, a shiny cobra of half-digested toffee apple, candy floss, and three of Fryer Tuck's All-American Taste-Tastic Hot Dogs, highly recommended, writhing longer.

From "Black Swan Green" by David Mitchell

Related Words

• faucet
• pipe
• spigot