also: ラジエター · ラジエータ · ラジエタ · ラジェーター
Refers to a device for heating a room or cooling an engine, matching the English loanword usage.
It was cold, so I turned on the radiator.
Steam is coming out of the car's radiator.
The car's radiator broke down and water leaked out.
You need to replace the radiator coolant periodically.