\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.