- mainline⇄adj. traveling on or situated along a main line.
Ex. mainline towns. - mainline⇄mainline, adjective, verb, -lined,-lining.
- mainline⇄v.i., v.t. (U.S. Slang.)1. to inject a narcotic, especially heroin, directly into a vein.
2. to absorb or consume something in excessive amounts.
Ex. Queens ... is seen as a brooding borough of dark brick where the ungroomed sit around in th