-ād.ə(r), -ātə- sometimes chiefly dial ˈrad- noun
( -s )
Etymology: radiate (I) + -or
: one that radiates something (as heat, light, or sound): as
a. : any of various devices (as a nest of pipes containing circulating steam or hot water for heating a room, a system of rings on a gun barrel for cooling it, or a nest of tubes with large radiating surface for cooling circulating water) for heating external objects or for cooling an internal substance by radiation
b.
(1) : transmitter a
(2) : transmitter b
(3) : a transmitting antenna
c. : a radioactive substance