·noun One who, or that which, heats.
II. Heater ·noun Any contrivance or implement, as a furnace, stove, or other heated body or vessel, ·etc., used to impart heat to something, or to contain something to be heated.
A drover: from their frequent sleeping on hay mows. CANT. ...
Dictionary of The Vulgar Tongue by Francis Grose
A contrivance for increasing the temperature of the steam to the extent that it would lose on its wa...
The Sailor's Word-Book