- to inject a narcotic, especially heroin, directly into a vein.
- to use or enjoy something without restriction: to mainline on TV movies.
- to inject (a narcotic, especially heroin) directly into a vein.
- to use, enjoy, or imbibe (something) without restriction: mainlining coffee all day long.
- having a principal, established, or widely accepted position; major; mainstream: the membership of mainline churches.
Origin of mainline
Related Wordsprime, major, dominant, preeminent, outstanding, leading, primary, key, paramount, main, predominant, prominent, booming, comfortable, well-to-do, well-heeled, well-off, affluent, rich, wealthy
Examples from the Web for mainline
Mainline and black Protestants rarely regard Southern Baptists and Mormons as political allies.Even Conservative Evangelical Support Couldn’t Save Immigration Reform
July 6, 2014
And mainline Protestant denominations find themselves shrinking.Is American Christianity Becoming a Workout Cult?
April 27, 2014
Mainline Protestant denominations are in marked decline and Evangelical Christianity is in slow retrograde.Demographics Or Destiny in 2016
March 10, 2014
This collaboration is different from our mainline collection, but the PETER PILOTTO woman is the same.Peter Pilotto Makes Target Go Pop in Latest Collaboration
The Fashion Beast Team
February 7, 2014
The decline of mainline Protestantism has also undermined this sort of prudent, empirically-minded Republicanism.Sam’s Club Republicans Vs. the Tea Party
October 29, 2013
Sidetrack your emotions if you can and stick to the mainline!Cleek of Scotland Yard
Thomas W. Hanshew
Word Origin and History for mainline
also main-line, 1934, from main line in American English slang sense "principal vein into which drugs can be injected" (1933).