Heater (noun)

1. A device for heating a room or other space.
2. A device for heating water or other fluids.
3. A part of a vehicle, such as a car or a plane, that provides heat to the passengers.

Origin:

Heater (n.) from heat (v.).

Examples:

1. He was turning on the heater.
2. She was using a portable heater.
3. The heater was not working properly.
4. He was fixing the water heater.
5. She was adjusting the temperature on the heater.