ˈtäləˌdēn, -_də̇n noun
( -s )
Etymology: International Scientific Vocabulary tol- + -idine
: any of several isomeric aromatic diamines [−C 6 H 3 (CH 3 )NH 2 ] 2 that are homologues of benzidine and made from the nitrotoluenes by alkaline reduction: as
a. : a pearly crystalline compound made from ortho -nitrotoluene and used as a dye intermediate and in chemical analysis (as in testing for free chlorine after chlorination of water because of the intense blue color it gives with chlorine); 3,3′-dimethyl-benzidine — called also ortho-tolidine
b. : a crystalline compound made from meta -nitrotoluene and used as a dye intermediate; 2,2′-dimethyl-benzidine — called also meta-tolidine