What is the X in X-mas?
Fluorescence and Phosphorescence -- Prof. E. Wiedmann has made a new study of these phenomena. He proposes the general name luminescence for evolutions of light which do not depend on the temperature of the substance concerned. ["Photographic News," April 20, 1888]
luminescence lu·mi·nes·cence (lōō'mə-něs'əns)
The emission of light that does not derive energy from the temperature of the emitting body, as in fluorescence and bioluminescence.
The light so emitted.