/par"euh kwaht'/ , n. Chem.
a toxic herbicide, C 12 H 14 N 2 ·2CH 3 SO 4 , applied to food and flower crops and to highway borders as a defoliant and weed-killer.
[ 1960-65; PARA- 1 + QUAT(ERNARY), in reference to the bond between the two pyridyl groups, which is in the para position with respect to their quaternary nitrogen atoms ]