a principal line or route of a railroad, as contrasted with a branch or secondary one.
a principal highway.
Slang.
a prominent and readily accessible vein of the body that may be used for a narcotic's injection.
the act of mainlining.
a fashionable residential district west of Philadelphia.
any fashionable district where socially prominent people live.
railways
the trunk route between two points, usually fed by branch lines
( as modifier )
a main-line station
a main road
First recorded in 1835–45
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Cardinale grew up in Villanova, Penn., an affluent suburb on Philadelphia’s Main Line, and attended The Haverford School, an all-boys prep school.
From The Wall Street Journal • Jan. 16, 2026
The West Coast Main Line does not have the capacity to run any more trains, while the East Coast Mainline's new December timetable will make it much busier, he says.
From BBC • Dec. 21, 2025
The train journey from London Liverpool Street to Chelmsford railway station takes 30-40 minutes, on the Great Eastern Main Line which runs as far north as Norwich.
From BBC • Sep. 4, 2025
Wallis Huberta Annenberg was born in the affluent Main Line area of Philadelphia and grew up, from age 10, in Washington, D.C.
From Los Angeles Times • Jul. 28, 2025
It’s on the prestigious Main Line, just twenty-five minutes outside Philadelphia, on a rolling campus surrounded by overgrown foliage.
From "The Other Wes Moore: One Name, Two Fates" by Wes Moore
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
