Noun
a fluid agent (gas or liquid) that produces cooling; especially one used to cool a system by transferring heat away from one part to another
Source: WordNetIn his mind Vaughan saw the whole world dying in a simultaneous auto disaster, millions of vehicles hurled together in a terminal congress of spurting loins and engine coolant. J. G. Ballard
he added more coolant to the car's radiator Source: Internet
the atomic reactor used a gas coolant Source: Internet
lathe operators use an emulsion of oil and water as a coolant for the cutting tool Source: Internet
Additionally a regulated overpressure in the cooling system (regulated and maintained by the coolant filler cap spring pressure) prevents the forming of cavitation. Source: Internet
A higher temperature coolant would be less dense, and therefore a less effective moderator. Source: Internet