coolant

American  

[koo-luhnt] / ˈku lənt /

noun

• coolants
  plural

1. a substance, usually a liquid or a gas, used to reduce the temperature of a system below a specified value by conducting away the heat produced in the operation of the system, as the liquid in an automobile cooling system or the fluid that removes heat from the core of a nuclear reactor.

2. a lubricant that dissipates the heat caused by friction.

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coolant British  

/ ˈkuːlənt /

noun

1. a fluid used to cool a system or to transfer heat from one part of it to another

2. a liquid, such as an emulsion of oil, water, and soft soap, used to lubricate and cool the workpiece and cutting tool during machining

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Other Word Forms

Noun Inflected Forms

• coolants
  plural

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Etymology

Origin of coolant

First recorded in 1925–30; cool + -ant

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Example Sentences

See Examples For:

coolant coolants

But the new facilities increasingly use closed-loop liquid cooling, which continually recirculates coolant instead.

From MarketWatch ● Sep. 18, 2026

Some drivers prefer not to use the cooling kit because of discomfort, and because there have been issues with the coolant running out before a grand prix is finished.

From BBC ● Sep. 3, 2026

It can take years to build special equipment, such as pressure vessels, steam generators and reactor coolant pumps, the 170 metric ton hermetically sealed systems that move water through the reactor core.

From The Wall Street Journal ● Jun. 23, 2026

And Rubio carried out the longest single spaceflight by a US astronaut in history, spending 371 days in space after a coolant leak prolonged the journey.

From Barron's ● Jun. 9, 2026

Rods remain submerged in the coolant and radiation shield of the water while they are being moved.

From "Meltdown" by Deirdre Langeland

It has also acquired Anchemco’s automotive business specializing in brake fluids, coolants and diesel exhaust fluids.

From The Wall Street Journal ● Apr. 21, 2026

These coolants are essential in fusion reactors to extract heat and breed tritium, but their corrosive nature threatens the integrity of the structural materials used.

From Science Daily ● Nov. 25, 2024

Whereas other advanced reactor designs rely on exotic coolants, NuScale’s sticks to water.

From Science Magazine ● Nov. 10, 2023

Trees are natural coolants and lower the risk of respiratory and heat-related illnesses such as those seen during this summer’s record heat wave.

From National Geographic ● Oct. 9, 2023

She was frosted already by the interhull coolants, and as I approached the high port slid open and the exitway was extruded, a graceful curve down onto the ice.

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

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