main line


a principal line or route of a railroad, as contrasted with a branch or secondary one.
a principal highway.
  1. a prominent and readily accessible vein of the body that may be used for a narcotic's injection.
  2. the act of mainlining.

Origin of main line

First recorded in 1835–45

Main Line


a fashionable residential district west of Philadelphia.
any fashionable district where socially prominent people live.
Related formsMain-Line, adjectiveMain-Lin·er, noun Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for main line

Historical Examples of main line

  • Two main-line routes are provided to the Grand Junction gateway.

  • I didn't want to advertise our troubles to a main-line official.

  • The main-line engine she's built for speed as well as power.

  • Banks and the cowboys, waiting breathless, saw Harvey with a determined lurch close the main-line contact.

    The Nerve of Foley

    Frank H. Spearman

  • Then once more he caught up the severed end of the main-line wire, and touched the opposite side of the instrument.

    The Young Railroaders

    Francis Lovell Coombs

British Dictionary definitions for main line

main line


  1. the trunk route between two points, usually fed by branch lines
  2. (as modifier)a main-line station
US a main road

verb mainline

(intr) slang to inject a drug into a vein

adjective mainline

having an important position, esp having responsibility for the main areas of activity
Derived Formsmainliner, noun
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for main line

"principal line of a railway," 1841; meaning "affluent area of residence" is by 1917, originally (with capitals) that of Philadelphia, from the "main line" of the Pennsylvania Railroad which added local stops to a string of backwater towns west of the city late 19c. that helped turn them into fashionable suburbs.

The Main Line, Philadelphia's most famous suburban district, was deliberately conceived in the 1870's and 1880's by the [Pennsylvania] Railroad, which built high-toned housing developments, ran hotels, more or less forced its executives to plunk their estates out there, and created a whole series of somewhat spurious Welsh towns along the railroad tracks. ... Now everybody assumes these all date from 1682, like the Robertses; but as Chestnut Hill people like to say, "nobody but Welsh peasants lived on the Main Line till the Railroad built it up." [Nathaniel Burt, "The Perennial Philadelphians," 1963]

The original station stops were, in order out from the city, Overbrook, Merion, Narberth, Wynnewood, Ardmore, Haverford, Bryn Mawr, Paoli. The train line for commuters along it is the Paoli Local.

Online Etymology Dictionary, © 2010 Douglas Harper