mainlined; mainlining; mainlines
slang
: to take by or as if by injecting into a principal vein
slang
: to mainline a narcotic drug
: being part of an established group
also
: being in the mainstream
1
: a principal highway or railroad line
2
slang
: a principal vein of the circulatory system
Examples of mainline in a Sentence
Verb
His addiction grew worse when he began mainlining.
Recent Examples on the Web
Jack King, Vulture, 13 Oct. 2024
The season is long, and cold, and involves a lot of staying in bed on your laptop until 1 pm and also mainlining Oreos while half-watching The Holiday on your mum’s sofa and scrolling Instagram.
—Daisy Jones, Vogue, 22 Oct. 2024
John W. Dean, MSNBC Newsweek, 7 Apr. 2025
Full Story Tax Watch Senate budget calls for fraction of cuts sought by House
The Senate voted Thursday to advance its budget resolution, setting up a weekend vote for the upper chamber’s precursor bill for Republicans’ mainline tax cut and spending legislation.
—Aris Folley, The Hill, 4 Apr. 2025
Ewan Spence, Forbes.com, 11 Apr. 2025
The first Amtrak Airo train will debut in 2026, but eventually, these trains will be rolled out on several of the rail company’s main lines.
—Evie Carrick, Travel + Leisure, 24 Mar. 2025
See All Example Sentences for mainline
Examples are automatically compiled from online sources to
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Verb
For the guys below the line — not least poor Daniel, who spends his drive to work mainlining his vape while listening to a woefully inadequate meditation tape — there’s existential terror in the air apropos of the arrival of new producer Anita at the end of episode one.
—Jack King, Vulture, 13 Oct. 2024
The season is long, and cold, and involves a lot of staying in bed on your laptop until 1 pm and also mainlining Oreos while half-watching The Holiday on your mum’s sofa and scrolling Instagram.
—Daisy Jones, Vogue, 22 Oct. 2024
Adjective
Predator: Badlands Release Date Predator: Badlands is the seventh film in the mainline Predator series and ninth in the overall franchise.
—John W. Dean, MSNBC Newsweek, 7 Apr. 2025
Full Story Tax Watch Senate budget calls for fraction of cuts sought by House
The Senate voted Thursday to advance its budget resolution, setting up a weekend vote for the upper chamber’s precursor bill for Republicans’ mainline tax cut and spending legislation.
—Aris Folley, The Hill, 4 Apr. 2025
Noun
In terms of devices, Google looks to be settled on a main line of the Pixel and Pixel Pro smartphones (with Pro and Pro XL models) in Q3, and the mid-range Pixel A Series in Q1.
—Ewan Spence, Forbes.com, 11 Apr. 2025
The first Amtrak Airo train will debut in 2026, but eventually, these trains will be rolled out on several of the rail company’s main lines.
—Evie Carrick, Travel + Leisure, 24 Mar. 2025
See All Example Sentences for mainline
Cite this Entry
“Mainline.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/mainline. Accessed 22 Apr. 2025.
Copy CitationMedical Definition
mainline
1 of 2 verb
main·line
ˈmān-ˈlīn 
mainlined; mainlining
slang
: to take by or as if by injecting into a principal vein
slang
: to mainline a narcotic drug (as heroin)
main line
2 of 2 noun
slang
: a principal vein of the circulatory system
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