\In"du*line\, n. [Perh. fr. indigo.] (Chem.)
(a) Any one of a large series of aniline dyes, colored blue
    or violet, and represented by aniline violet.
(b) A dark green amorphous dyestuff, produced by the
    oxidation of aniline in the presence of copper or
    vanadium salts; -- called also {aniline black}.