fluorescein \fluo`res"ce*in\, fluoresceine \fluo`res"ce*ine\,
fluorescein \flu`o*res"ce*["i]n\, n. (Chem.)
   A yellowish red, crystalline substance, C20H12O5, produced
   by heating together phthalic anhydride and resorcin; -- so
   called, from the very brilliant yellowish green fluorescence
   of its alkaline solutions. It has acid properties, and its
   salts of the alkalies are known to the trade under the name
   of uranin.

   Syn: fluorescein, fluorescent dye, resorcinolphthalein.
        [1913 Webster]

Uranin \U"ra*nin\, n. (Chem.)
   An alkaline salt of fluorescein, obtained as a brownish red
   substance, which is used as a dye; -- so called from the
   peculiar yellowish green fluorescence (resembling that of
   uranium glass) of its solutions. See Fluorescein.
   [1913 Webster]