(n.) 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 so-called aniline dyes, as fuchsine, aniline red, etc. By extension, any one of the series of substances derived from, or related to, rosaniline proper.