The Collaborative International Dictionary of English v.0.48:

Rosaniline \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.
   [1913 Webster]