\Ros*an"i*line\ (? or ?), n. [Rose + aniline.]
(Chem.)
A complex nitrogenous base, {C20H21N3O}, obtained by
oxidizing a mixture of aniline and toluidine, as a colorless
crystalline substance which forms red salts. These salts are
essential components of many of the socalled aniline dyes, as
fuchsine, aniline red, etc. By extension, any one of the
series of substances derived from, or related to, rosaniline
proper.