mainline
Americanverb (used without object)
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mainlines,
present (3rd person singular)
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mainlined,
past participle, past
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mainlining
present participle
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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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mainlines,
present (3rd person singular)
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mainlined,
past participle, past
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mainlining
present participle
-
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:
Assaults on the mainline railway are recorded according to their type.
From BBC ● Sep. 24, 2026
DWP plans to replace about 45 miles of mainline, which deliver water to individual services across neighborhoods, this fiscal year.
From Los Angeles Times ● Jul. 25, 2026
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
Given that the bulk of mainline members and leaders are elderly, a grassroots insurgency makes sense.
From The Wall Street Journal ● Jun. 25, 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
The break, which happened early Thursday, was on a riveted steel pipe from 1916 that forms the major arteries for water delivery from reservoirs and tanks to smaller distribution mainlines across Los Angeles.
From Los Angeles Times ● Jul. 17, 2026
He mainlines all of his romantic entanglements as if they were the antidote to his unresolved traumas.
From Salon ● Apr. 25, 2025
The line was used to transport agricultural products and produce as a crucial connector to other mainlines down the Columbia River.
From Seattle Times ● Sep. 7, 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
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
All of that is mainlined into her songs.
From Slate ● Mar. 29, 2019
I mean, they’re really being mainlined right into your brain.
From Washington Post ● Oct. 15, 2018
He mainlined fantasy, horror, science fiction and drama growing up, and started as a fanboy.
From New York Times ● Oct. 20, 2016
Sitting down for a filling breakfast, instead of mainlining a protein bar, can feel irresponsible.
From Slate ● Sep. 23, 2026
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
Sheek Louch, who sounds like he’s been mainlining Ka records, has an excellent verse on “Donda.”
From New York Times ● Aug. 31, 2021
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.
