\Lu`mi*nes"cence\, n. [See {Luminescent}.]
1. (Physics) Any emission of light not ascribable directly to
   incandescence, and therefore occurring at low
   temperatures, as in phosphorescence and fluorescence or
   other luminous radiation resulting from vital processes,
   chemical action, friction, solution, or the influence of
   light or of ultraviolet or cathode rays, etc.

2. (Zo["o]l.)
   (a) The faculty or power of voluntarily producing light,
       as in the firefly and glowworm.
   (b) The light thus produced; luminosity; phosphorescence.