(1) (physics) The electromagnetic radiation of any wavelength, or sometimes only referring to a range of wavelength (about 400-700 nm) visible to an unaided human eye.
(2) A source of illumination, e.g. a lamp or an electric lighting fixture.
(3) The sensation of perceiving light.
To illuminate or to provide illumination; to ignite; to give out or fill with light.
(1) Characterized by light (illumination).
(2) Not dark in color; fair.
(3) Low in content or amount, e.g. low in sugar or starch.
(4) Applying slight force or pressure.
Certain organisms are capable of producing and emitting visible radiation. Examples of such organisms are fireflies, glow worms, Jack O’Lantern mushroom, ghost fungus, Anglerfish, Aequorea victoria (a jellyfish), dinoflagellates, etc.
Word origin: Old English lēoht. Cognate with Dutch licht, German Licht.
See also: wavelength