Source : Webster's Revised Unabridged Dictionary (1913)

Indoxyl \In*dox"yl\, n. [Indigo + hydroxyl.] (Chem.)
   A nitrogenous substance, {C8H7NO}, isomeric with oxindol,
   obtained as an oily liquid.

Oxindol \Ox*in"dol\, n. [Oxygen + indol.] (Chem.)
   A white crystalline nitrogenous substance ({C8H7NO}) of the
   indol group, obtained by the reduction of dioxindol. It is a
   so-called lactam compound.