mainline

1 of 3

verb

main·​line ˈmān-ˌlīn How to pronounce mainline (audio)
mainlined; mainlining; mainlines

transitive verb

slang : to take by or as if by injecting into a principal vein

intransitive verb

slang : to mainline a narcotic drug

mainline

2 of 3

adjective

: being part of an established group
also : being in the mainstream

main line

3 of 3

noun

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
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
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
Both the mainline entries and Warzone are iterating upon each other as Warzone takes on mechanical innovations such as movement changes while titles like Modern Warfare III have utilized the battle royale’s maps and armor system within their campaigns. Cade Onder, Rolling Stone, 25 Oct. 2024 Almost all mainline Christian faiths have seen precipitous drops in the pews, but the smaller presence of Catholicism is particularly evident in Milwaukee, where Catholic churches historically have anchored neighborhoods and acted as virtual community centers. Sophie Carson, Journal Sentinel, 4 Nov. 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 

Word History

First Known Use

Verb

1938, in the meaning defined at transitive sense

Adjective

1941, in the meaning defined above

Noun

1841, in the meaning defined at sense 1

Time Traveler
The first known use of mainline was in 1841

Dictionary Entries Near mainline

Mainland

mainline

main line

Cite this Entry

“Mainline.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/mainline. Accessed 28 Nov. 2024.

Medical Definition

mainline

1 of 2 verb
main·​line ˈmān-ˈlīn How to pronounce mainline (audio)
mainlined; mainlining

transitive verb

slang : to take by or as if by injecting into a principal vein

intransitive verb

slang : to mainline a narcotic drug (as heroin)

main line

2 of 2 noun
slang
: a principal vein of the circulatory system
Last Updated: - Updated example sentences
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