radiation
ra.di.a.tion \.ra-d-e--'a--sh*n\ \-shn*l, -sh*n-*l\ \'ra-d-e--.a-t-iv\ n 1a: the action or process of radiating 1b1: the process of emitting radiant energy in the form of waves or particl es 1b2: the combined processes of emission, transmission, and absorption of ra diant energy 2a: something that is radiated 2b: energy radiated in the form of waves or particles 3: radial arrangement 4: RADIATOR - ra.di.a.tion.al aj