In"dol (&ibreve;n"dōl), 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.