main·​lin·​er | \ ˈmān-ˌlī-nər How to pronounce mainliner (audio) \
plural mainliners

Definition of mainliner

1 : a member of a mainline group (such as a church) Of the remaining mainliners, the Christian Church (Disciples of Christ) has suffered most. It has lost 40 percent of its members and now claims only 1,146,000 faithful.— Kenneth L. Woodward, Newsweek, 22 Dec. 1986
2 informal : a person who injects a drug into a vein : a person who mainlines a drug She holds nothing back about the awful things done to her, or about her attraction to the social danger zones inhabited by strippers, heroin mainliners, rhino poachers, and guerrillas.— Gilbert Taylor, Booklist, 1 Dec. 2000

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First Known Use of mainliner

1934, in the meaning defined at sense 2

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The first known use of mainliner was in 1934

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Cite this Entry

“Mainliner.” Dictionary, Merriam-Webster, Accessed 28 Jun. 2022.

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