\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.