Source : Webster's Revised Unabridged Dictionary (1913)

Euchroic \Eu*chro"ic\, a. [Gr. ? well-colored; ? well + ?
   color.] (Chem.)
   Having a fine color.

   {Euchroic acid} (Chem.), an organic, imide acid, obtained as
      a colorless crystalline substance, {C12H4N2O8} by heating
      an ammonium salt of mellitic acid. By reduction it is
      changed to a dark blue substance (euchrone), -- hence its
      name.