Ra"di*a`tor (?), n. 1. Any of various devices for cooling an internal substance by radiation, as a system og rings on a gun barrel for cooling it, or a nest of tubes with large radiating surface for cooling circulating water, as in an automobile.

2. (Wireless Teleg.) An oscillator.

Ra"di*a`tor (-ā`t&etilde;r), n. That which radiates or emits rays, whether of light or heat; especially, that part of a heating apparatus from which the heat is radiated or diffused; as, a steam radiator.

Ra"di*a`tor (?), n. 1. Any of various devices for cooling an internal substance by radiation, as a system og rings on a gun barrel for cooling it, or a nest of tubes with large radiating surface for cooling circulating water, as in an automobile.

2. (Wireless Teleg.) An oscillator.

• Any thing which radiates or emits rays.
  
• (Automotive) A device that lowers engine coolant temperature by conducting heat to the air, through metal fins.
  
• (Buildings) A type of heater that conducts heat from hot water to the air, through metal fins.
  
• (Electronics) A type of antenna