is a specific kind of: actinic radiation, actinic ray.

is a broader term that covers: beam, beam of light, irradiation, light beam, ray, ray of light, shaft, shaft of light | candle flame, candlelight | corona | counterglow, gegenschein | daylight | firelight | fluorescence | friar's lantern, ignis fatuus, jack-o'-lantern, will-o'-the-wisp | gaslight | glow, glowing, radiance | glow | half-light | glow, incandescence | lamplight | luminescence | meteor, shooting star | Moon, moonlight, moonshine | starlight | sun, sunlight, sunshine | scintillation | streamer | torchlight | twilight ... show more.

is a part of: electromagnetic spectrum.

domain category: natural philosophy, physics.

derivation: illume, illuminate, illumine, light, light up.