the main line 

A suburb just outside of Philadelphia known for its reputation of preppy schools, moms, kids, and pretty much everything else. All of the private schools including The Haverford School, The Baldwin School, The Agnes Irwin School, and The Episcopal Academy, are known for their great education and scandalous secrets. To sum it all up the mainline is like the 90210 with rich preppy families who send their children to private schools just to show off how much money they have. The mainline is a community of dirty, rich, and prestigious people who will do anything to one up anyone else.

Don't trust the people on the main line

the main line by Hdbakdbejfbd July 1, 2014

The main line 

This is a definition of the "Main Line", a line of suburbs right outside of Philadelphia. First, all the little white boys think that they are gang members and go biking around the neighborhood that they call the "streets" or the "hood". No, just no. The rich main line moms are fucking annoying and act like their kids a miracle children sent from heaven but little do they know that they all JUUL and smoke whatever shit they are doing at frickin bar mitzvahs. There are many public schools, and some private schools. The kids, oh the kids, are fucking donkeys. With Wiggas, JAPS, kids that could possibly shoot up their school in the future, and stoners, the main line kids can not get any worse. DO NOT, I REPEAT, DO NOT go to Suburban Square, if you want to stay away from these pieces of donkey shit kids. Overall, no hate on the mainline(my hometown yo),but It is a sack of balls that is consumed with snobby ass kids who will die because their juuls killed them. . It is a fucking void that you will find yourself forever empty in there because everyone is jewish and u feel left out because your not jewish and its the trend to be jewish and have a fun mar mitzvah where your friends give speeches for you :(.

ben rosenberg from the main line: yo yo yo gang gang all on that gang shit my homie lets go bike to suburban square yo
jack goldstein: sounds like a good idea my brotha but I got some shit to do

ben rosenberg: what u gotta do
jack goldstein : I got piano practice

ben rosenberg: aww damn aint that a bitch

The main line by urbangod11 September 17, 2019

Jack the mainline 

Doing heroin intravenously in the style of Robbie Williams. See also rock the mainline.

From Robbie Williams' "Rudebox":

"Ok then check the tan line
Make your body shape
Like you're stood on a landmine
Call me on my mobile
Not the landline
And jack the mainline
At the same time"

Jack the mainline by Some Fresh Money September 18, 2007

Rock the mainline 

To get "high" on heroine through the means of an introvenus-needle. I.e. - Shooting up.

Addict: Yo, dog... Yo got the shit to lemme rock tha mainline?
Dealer: Fo' sizzle ma nizzle, that'll be fiddy.

Rock the mainline by God May 20, 2003