- fluorescence [flo͞o΄ə res′əns]n.[< FLUOR(SPAR) + -ESCENCE]1. the property of a substance, such as fluorite, of producing light while it is being acted upon by ultraviolet rays, X-rays, or other forms of radiant energy2. the production of such light3. light so produced
English World dictionary. V. Neufeldt. 2014.