main line
noun
a principal line or route of a railroad, as contrasted with a branch or secondary one.
main line
1 Americannoun
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a principal line or route of a railroad, as contrasted with a branch or secondary one.
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a principal highway.
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Slang.
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a prominent and readily accessible vein of the body that may be used for a narcotic's injection.
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the act of mainlining.
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Main Line
2
American
noun
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a fashionable residential district west of Philadelphia.
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any fashionable district where socially prominent people live.
main line
British
noun
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railways
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the trunk route between two points, usually fed by branch lines
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( as modifier )
a main-line station
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a main road
verb
adjective
Other Word Forms
Etymology
Origin of main line
First recorded in 1835–45
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
Rupireddy called Late Stage’s main line dozens of times, but he said no one answered.
From The Wall Street Journal ● Aug. 6, 2026
Warwickshire Police said its main line of inquiry was that a vehicle had hit the man and left the scene.
From BBC ● Apr. 5, 2026
Pike followed the main line — called the trunk line — which had hoses branching off in other directions.
From Los Angeles Times ● Mar. 11, 2026
The depletion of mangrove forests along the shoreline - the coast’s main line of defence against erosion - is to blame.
From BBC ● Aug. 13, 2024
This divide-and-conquer strategy is better than repeatedly allowing counterexamples to intrude into the main line of an argument while browbeating readers into looking away.
From "The Sense of Style" by Steven Pinker
Network Rail has warned that the Midland Main Line will remain closed to East Midlands Railway and Thameslink services until the end of the week.
From BBC ● Jun. 24, 2026
Lev, 49, started reaching out to other parents here, in Philadelphia’s wealthy Main Line suburbs, and he found hundreds of families who felt the same way.
From The Wall Street Journal ● Jun. 21, 2026
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 operator said services along the Highland Main Line, between Inverness and Perth, was running.
From BBC ● Jan. 5, 2026
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.
