- the emission of radiation, especially of visible light, by a substance during exposure to external radiation, as light or x-rays.
- the property possessed by a substance capable of such emission.
- the radiation so produced.
- physics
- the emission of light or other radiation from atoms or molecules that are bombarded by particles, such as electrons, or by radiation from a separate source. The bombarding radiation produces excited atoms, molecules, or ions and these emit photons as they fall back to the ground state
- such an emission of photons that ceases as soon as the bombarding radiation is discontinued
- such an emission of photons for which the average lifetime of the excited atoms and molecules is less than about 10 –8 seconds
- the radiation emitted as a result of fluorescence
