Source : Webster's Revised Unabridged Dictionary (1913)

Indol \In"dol\, n. [Indigo + -ol of phenol.] (Physiol. Chem.)
   A white, crystalline substance, {C8H7N}, obtained from blue
   indigo, and almost all indigo derivatives, by a process of
   reduction. It is also formed from albuminous matter, together
   with skatol, by putrefaction, and by fusion with caustic
   potash, and is present in human excrement, as well as in the
   intestinal canal of some herbivora.