1. (US prison) pertaining to the main prison population (and the rules to which it is subjected).
|Rough Stuff 181: They get their mates to furnish them with work [...] where they can get some food which is not the ‘main line chuck’ (regulation prison food).|
|We Who Are About to Die 92: Mainline chow is another matter.|
|On the Yard (2002) 251: No reason for you to eat mainline [...] You never ate mainline in Tracy, did you?|
|Mr Blue 151: The condemned, who were far fewer and more quickly executed back then, were fed much better than the mainline convicts.|
2. (orig. US drugs) pertaining to narcotics use and addiction.
|Man Who Was Not With It (1965) 278: He didn’t have to sell mainline sugar in addition.|
|Gay Detective (2003) 79: You can get anything in that joint from a piece of trade to a main line shot.|
|Ringolevio 40: He had given himself his wings – his first mainline fix.|