noun.
A dark green synthetic dyestuff, C20H19N3·HCl, used to make a purple-red dye employed in coloring textiles and leather and as a bacterial stain.
The Century Dictionary and Cyclopedia
noun.
An aniline dye prepared by the action of weak oxidizing agents, such as arsenic acid, nitrobenzene, etc., on commercial aniline oil, and subsequent treatment of the rosaniline so formed with common salt.