luminescence

When some object gives off light, that light is called luminescence. The luminescence of a lighthouse helps keep boats safe on foggy nights.

Glow-in-the-dark stars stuck to your bedroom ceiling have a luminescence you can see when you turn out the light at night, and lightning bugs blink on and off with luminescence in the summertime. Luminescence, scientifically speaking, describes a glow or light that's emitted at a cool temperature, rather than one caused by a fire, for example. The Latin root is lumen, or "light."

Definitions of luminescence
  1. noun
    light not due to incandescence; occurs at low temperatures
    synonyms: phosphorescence
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    types:
    bioluminescence
    luminescence produced by physiological processes (as in the firefly)
    chemiluminescence
    luminescence resulting from a chemical reaction as the oxidation of luciferin in fireflies
    type of:
    light, visible light, visible radiation
    (physics) electromagnetic radiation that can produce a visual sensation
  2. noun
    light from nonthermal sources
    synonyms: glow
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    type of:
    brightness, brightness level, light, luminance, luminosity, luminousness
    the quality of being luminous; emitting or reflecting light
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