Source : Webster's Revised Unabridged Dictionary (1913)

Chrysophanic \Chrys`o*phan"ic\, a.
   Pertaining to, or derived from, or resembling, chrysophane.

   {Chrysophanic acid} (Chem.), a yellow crystalline substance
      extracted from rhubarb, yellow dock, sienna, chrysarobin,
      etc., and shown to be a derivative of an anthracene. It is
      used in the treatment of skin diseases; -- called also
      {rhein}, {rheic acid}, {rhubarbarin}, etc.