cool·​ant ˈkü-lənt How to pronounce coolant (audio)
: a usually fluid cooling agent

Examples of coolant in a Sentence

Recent Examples on the Web First, a Soyuz capsule — the Russian spacecraft that had brought Rubio to the ISS last September — sprung a coolant leak in mid-December, jeopardizing his ride home. Daniel Wu, Washington Post, 21 Sep. 2023 The mission was only supposed to last six months, but the ship that was supposed to bring the crew home had a coolant leak and was deemed unsafe. Jon Michael Raasch Fox News, Fox News, 19 Sep. 2023 Launched last September 21, Prokopyev, Petelin and Rubio originally planned to come home in March, but their Soyuz MS-22 ferry ship suffered a massive coolant leak in December, presumably due to a micrometeoroid impact. William Harwood, CBS News, 12 Sep. 2023 But as they are packed into larger groups for grid-scale systems, testing becomes more complex, and the pathways to ignition multiply: coolant leaks, shorting electronics, faulty installation. Gregory Barber, WIRED, 8 Sep. 2023 But the Russian Soyuz spacecraft that carried him and two Russian colleagues to the space station sprang a coolant leak late last year. Jackie Wattles, CNN, 3 Sep. 2023 After a June fire sparked by a coolant leak in a battery at the Nikola Corp.’s headquarters in Phoenix, the electric truck manufacturer announced a recall of 209 of its Tre electric battery trucks. The Arizona Republic, 16 Aug. 2023 Internal investigations by Nikola’s safety and engineering teams indicate a single supplier component within its battery packs is the likely source of coolant leaks that a third party found to be the probable cause of the June truck fire., 14 Aug. 2023 In one-phase systems, a liquid coolant moves through the system and absorbs excess heat, which raises the liquid’s temperature. Issam Mudawar, The Conversation, 14 Sep. 2023 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'coolant.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

First Known Use

1915, in the meaning defined above

Time Traveler
The first known use of coolant was in 1915

Dictionary Entries Near coolant

Cite this Entry

“Coolant.” Dictionary, Merriam-Webster, Accessed 2 Oct. 2023.

Kids Definition


cool·​ant ˈkü-lənt How to pronounce coolant (audio)
: a usually fluid cooling substance

More from Merriam-Webster on coolant

Last Updated: - Updated example sentences
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!