mainline
Americanverb (used without object)
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to inject a narcotic, especially heroin, directly into a vein.
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to use or enjoy something without restriction.
to mainline on TV movies.
verb (used with object)
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to inject (a narcotic, especially heroin) directly into a vein.
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to use, enjoy, or imbibe (something) without restriction.
mainlining coffee all day long.
adjective
Other Word Forms
Inflected Forms
Participles
Conjugated Forms
Present
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mainlinesimple
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mainlinessimple
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have mainlinedperfect
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has mainlinedperfect
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am mainliningprogressive
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are mainliningprogressive
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is mainliningprogressive
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have been mainliningperfect progressive
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has been mainliningperfect progressive
Past
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mainlinedsimple
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had mainlinedperfect
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was mainliningprogressive
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were mainliningprogressive
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had been mainliningperfect progressive
Future
Etymology
Origin of mainline
1935–40, v., adj. use of main line
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:
Located above a busy mainline railway station, MSG is slap bang in the beating heart of tourist and commercial Manhattan.
From Barron's ● Jul. 1, 2026
Technology will be rolled out across 1,400 trains on mainline nationalised services allowing them to connect to low-earth satellites, instead of mobile networks.
From BBC ● May 30, 2026
“We’ve made it kind of core to who Allegiant is to seek out opportunities that aren’t typically served by mainline carriers,” said Drew Wells, the airline’s chief commercial officer.
From The Wall Street Journal ● May 17, 2026
In 2026, the railway is used by regular passenger services, commuters, steam engines and even mainline trains travelling between London and Glasgow when a diversion is required.
From BBC ● May 1, 2026
But over the last forty years, evangelicals have pulled steadily closer in income and education to mainline Protestants in the historically affluent establishment denominations.
From "Class Matters" by The New York Times
He mainlines all of his romantic entanglements as if they were the antidote to his unresolved traumas.
From Salon ● Apr. 25, 2025
Afterward, Healey said the agency was underestimating the blockages on Westlake, including relocation of two sewer mainlines.
From Seattle Times ● Jul. 28, 2023
Current labor agreements ensure that freight trains on mainlines have two people — an engineer and conductor — onboard.
From Washington Post ● Mar. 3, 2023
Other operators will also run some trains on the east coast and west coast mainlines.
From BBC ● Jun. 15, 2022
Send this to someone who has a lot on her plate and needs this simple reminder as she mainlines caffeine.
From Slate ● Apr. 27, 2021
Johnson said that businesses had mainlined on low-wage imported labour for nearly 25 years and that they should now pay their workers more and invest more.
From Reuters ● Oct. 5, 2021
And most likely from doc-chockablock behemoth Netflix, whose mainlined hits “Frye: The Greatest Party That Never Happened” and “Tiger King” have inspired a term for reveling in the story of a scam unraveled: schaden-fraud.
From Los Angeles Times ● Mar. 11, 2021
In 10 weeks as an editing intern, I mainlined more plays, musicals, ballets and cabaret performances than many people see in their entire lives.
From New York Times ● Aug. 28, 2019
I mean, they’re really being mainlined right into your brain.
From Washington Post ● Oct. 15, 2018
It is less a video game than mainlined anxiety, its jump-scares timed with sadistic precision and its long, shadow-splashed corridors masterpieces of unnerving light design.
From Slate ● Feb. 1, 2011
The ubiquity of holiday songs also represents a rare monocultural music moment—even though listeners are spread across multiple streaming services and social-media platforms, many of them are mainlining the same tunes.
From The Wall Street Journal ● Dec. 14, 2025
In some ways, I feel like a conspiracy junkie who has relapsed, mainlining paranoia and dread.
From Salon ● Jul. 17, 2024
He was mainlining applause from the public gallery.
From Washington Post ● Jul. 8, 2022
VERDICT: Watching the 2021 Jets is like mainlining tryptophan.
From New York Times ● Nov. 21, 2021
Youths, I am told, speak of “hopium” and “copium,” but we need a word that incorporates the never-ending mainlining of information as well as the positive or negative cast of that information.
From Slate ● Nov. 6, 2020
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.
