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
Emily Mae Czachor, CBS News, 24 Dec. 2024
Many saw this year's UMC General Conference as an opportunity to start a new chapter in the life of the nation’s largest mainline Protestant denomination.
—Liam Adams, The Tennessean, 4 May 2024
Joe Cermele, Outdoor Life, 17 Oct. 2024
Set it up by tying a 12 to 24 inch length of 6-lb fluorocarbon to your main line, leaving a 3- to 4-inch tag end off your knot, and then tie on a 1/4 ounce casting weight to the bottom of the line.
—Kubie Brown, Outdoor Life, 3 Oct. 2024
See all Example Sentences for mainline 
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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
None of its mainline flights — which excludes those operated by its subsidiaries — were canceled on Sunday, Dec. 22, one of the busier days of the season, according to American.
—Emily Mae Czachor, CBS News, 24 Dec. 2024
Many saw this year's UMC General Conference as an opportunity to start a new chapter in the life of the nation’s largest mainline Protestant denomination.
—Liam Adams, The Tennessean, 4 May 2024
Noun
To avoid line twist and fouling, add a barrel swivel between your main line and leader when fishing a Krocodile.
—Joe Cermele, Outdoor Life, 17 Oct. 2024
Set it up by tying a 12 to 24 inch length of 6-lb fluorocarbon to your main line, leaving a 3- to 4-inch tag end off your knot, and then tie on a 1/4 ounce casting weight to the bottom of the line.
—Kubie Brown, Outdoor Life, 3 Oct. 2024
See all Example Sentences for mainline
Dictionary Entries Near mainline
Cite this Entry
“Mainline.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/mainline. Accessed 30 Dec. 2024.
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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