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)
-
mainlined,
past participle, past
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mainlining
present participle
-
to inject (a narcotic, especially heroin) directly into a vein.
-
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:
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
That, combined with the demographics of the mainline, makes some success seem inevitable.
From The Wall Street Journal ● Jun. 25, 2026
Is there any scope to speed up the delivery of new stations along the south Wales mainline, the first of which aren't projected to get underway until 2029?
From BBC ● May 29, 2026
Black Muslims came in many stripes, from mainline Nation of Islam to the splinter Five Percenters.
From "Newjack: Guarding Sing Sing" by Ted Conover
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
With sensation mainlined into our veins through our phones and laptops, art has little chance of keeping pace.
From Los Angeles Times ● Oct. 3, 2020
We mainlined Twitter, breaking news alerts and viral hoaxes masquerading as inside information; we stared slack-jawed at politicians' news briefings.
From Washington Post ● Apr. 17, 2020
He mainlined fantasy, horror, science fiction and drama growing up, and started as a fanboy.
From New York Times ● Oct. 20, 2016
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
Most of the time, if you’re on Twitter, you’re doing something else or mainlining information before leaving.
From Slate ● Apr. 13, 2023
‘Ready Player One’ feels like mainlining the VH1 show ‘I Love the ’80s.’
From Washington Post ● Jul. 14, 2021
I felt as if I were mainlining the whole cosmic force of basketball.
From New York Times ● Sep. 30, 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.
