1. [ noun ] any object that radiates energy
Related terms: natural_object radio_source radiate
2. [ noun ] heater consisting of a series of pipes for circulating steam or hot water to heat rooms or buildings
Related terms: heater heating_system
3. [ noun ] a mechanism consisting of a metal honeycomb through which hot fluids circulate; heat is transferred from the fluid through the honeycomb to the airstream that is created either by the motion of the vehicle or by a fan
Related terms: mechanism cooling_system radiator_cap