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

Etymology

Origin of coolant

First recorded in 1925–30; cool + -ant

Example Sentences

See Examples For:

coolant coolants

Engineers will carry out detailed inspections, collect flight data, remove reusable components such as avionics, and address any remaining hazards like excess fuel or coolant.

From Science Daily ● May 4, 2026

While most people might be familiar with helium as a filler for balloons, the gas is used as a coolant, including in semiconductor manufacturing and MRI machines.

From Salon ● Mar. 30, 2026

Most Americans think of helium as the gas that holds balloons aloft, but, more important, it is an essential coolant in MRI machines and semiconductor manufacturing.

From The Wall Street Journal ● Mar. 28, 2026

Sales of Chemours Opteon coolant, which can be used in data centers, grew 37% in the fourth quarter, to $243 million.

From Barron's ● Feb. 20, 2026

The reactor vessel, which holds the fuel, control rods, and coolant, lies at the center of a nuclear reactor building.

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