noun main·lin·er \ˈmān-ˌlī-nər\

Definition of mainliner



  1. 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. 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

Love words? You must — there are over 200,000 words in our free online dictionary, but you are looking for one that’s only in the Merriam-Webster Unabridged Dictionary.

Join MWU now and get access to America’s largest dictionary, with:

  • 300,000 words that aren't in our free dictionary
  • Expanded definitions, etymologies, and usage notes
  • Advanced search features
  • Ad free!


First Known Use of mainliner


Seen and Heard

What made you want to look up mainliner? Please tell us where you read or heard it (including the quote, if possible).


a trip made at another's expense

Get Word of the Day daily email!