uranin

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]