Any one of three metameric amido derivatives of toluene analogous to aniline, and called respectively
orthtoluidine,
metatoluidine, and
paratoluidine; especially, the commonest one, or
paratoluidine, which is obtained as a white crystalline substance. [
1913 Webster]
" It is used in the aniline dye industry, and constitutes the essential nucleus or radical of those dyes."
[1913 Webster]