1. (n.) The act of radiating, or the state of being radiated; emission and diffusion of rays of light; beamy brightness.

2. (n.) The shooting forth of anything from a point or surface, like the diverging rays of light; as, the radiation of heat.

X ray actinic ray actinism arc lighting asteroids atomic beam atomic ray attenuation aurora particles beam beam of light black and white blackout broadcast broadcasting chiaroscuro circumfusion contrast cosmic particles cosmic ray bombardment decorative lighting diffraction diffusion dilution direct lighting dispensation dispersal dispersion dissemination dissipation distribution divergence electric lighting emanation emission enlightenment evaporation expansion festoon lighting floodlighting fluorescent lighting fragmentation gamma ray gaslighting gleam glow lighting highlight highlights illumination incandescent lighting indirect lighting infrared ray intergalactic matter invisible radiation irradiance irradiancy irradiation leam light light and shade light source lighting luminous energy meteor dust impacts meteors overhead lighting patch pencil peppering photon photosensitivity propagation publication radiance radiancy radiant energy radiorays radius ray ray of light ribbon ribbon of light scattering scatterment shedding shotgun pattern sidelight solar rays sowing space bullets spattering splay spoke spot lighting spread spreading sprinkling stage lighting streak stream stream of light streamer strewing strip lighting the bends tonality ultraviolet ray violet ray visible radiation volatilization weightlessness