D defs.my
Entry 1 sense Webster, 1913

Fluorescence

/flo͝orˌ-ĕs'-əns/ · Flu·o·res·cence · IPA /flʊˈɹɛsəns/
01 n. A luminescence emitted by certain substances due to the absorption of radiation at one wavelength, and the almost instantaneous re-emission…
  1. 1.
    A luminescence emitted by certain substances due to the absorption of radiation at one wavelength, and the almost instantaneous re-emission of radiation at another, usually longer wavelength. The re-radiation stops almost as soon as the incident radiation is halted, thus distinguishing this phenomenon from phosphorescence, in which re-radiation of light may continue for some time after the incident radiation is halted.(Chemistry, Optics)