- any of several isomeric derivatives of biphenyl containing two methyl and two amino groups, especially the ortho isomer that is used as a reagent and in the preparation of dyes.
- any of several isomeric compounds, esp the ortho- isomer, which is a white or reddish crystalline substance used in the manufacture of dyes and resins. Formula: (C 6 H 3 NH 2 CH 3) 2
