mainline

Etymology

From main + line.

adj

1. Normal, principal or standard.
   At a time when mainline denominations are engaged in massive closures of small rural churches, independent charismatics are strategically helping to rechurch rural Canada. 2010, Steven M. Studebaker, Pentecostalism and Globalization
   This doesn’t necessarily mean Christians are joining mainline congregations — the survey measures self-identification, not church affiliation. It is, nevertheless, a striking turnabout after years when mainline Protestantism was considered moribund and evangelical Christianity full of dynamism. 2021-07-09, Michelle Goldberg, “The Christian Right Is in Decline, and It’s Taking America With It”, in The New York Times, →ISSN
2. (rail transport) Of or pertaining to the principal route or line of a railway.
3. (rail transport) Of or pertaining to a surface railway as distinct from an underground, elevated or light rail one.
4. (chess) Of a sequence of opening moves: being part of a main line ("a standard sequence of opening moves considered to be best play").
   After 3 e5 the Czech Benoni Defense is created. Unlike the mainline 3 e6, which aims for tactical counterplay in the center, Black aims for solidity there. He will choose later what flank to attack on. 2006-05-07, Robert Byrne, “For Most Players, Speed Chess Is Like a Keystone Kops Melee”, in The New York Times, archived from the original on 2023-02-01
   Short's pragmatic approach to the match was to avoid mainline theory and the teenager's computer preparation. 2010-05-21, Leonard Barden, “Nigel Short shows benefit of experience during series with Anish Giri”, in The Guardian
   The first classical game featured a fairly mainline Nimzo-Indian Defense, with the players following one of So's October 2021 games until move 20. 2022-04-04, Luci Kelemen, “Wesley So wins third leg of FIDE Grand Prix 2022 over Nakamura”, in Dot Esports, archived from the original on 2022-12-30

verb

1. (slang) To inject (a drug) directly into a vein.
   The patient skinpopped for 1½ years and then started to mainline heroin. 1968, Richard Brotman, Alfred M. Freedman, A Community Mental Health Approach to Drug Addiction, page 97
2. (by extension, informal, transitive) To consume voraciously.
   Last month, she lamented that her busy campaign schedule had kept her from mainlining Amazon’s new “Rings of Power” series. 2022-09-21, Jason Horowitz, “Hobbits and the Hard Right: How Fantasy Inspires Italy’s Potential New Leader”, in The New York Times, →ISSN
3. (computing, transitive) To integrate (code, etc.) into the main repository for a software project, rather than separate forks.

noun

1. (aviation) An airline's main operating unit, as opposed to codeshares or regional subsidiaries.
2. (rail transport) The principal route or line of a railway.
   Coordinate term: trunk line
3. (fishing">fishing) In longline fishing">fishing the central line to which the branch lines with baits are attached.
4. (plumbing) The pipeline carrying wastewater to the public drains or a septic tank.
   Many plumbers will tell you they don't go off property since that is the local water company's responsibility. Most local water companies would prefer that, if a line is snaked, it is snaked all the way to the mainline connection. 2007, Melvin Ladon White, Property Owner's Sewer and Drain Guide, page 31
   In addition, opportunities exist for the introduction of these organisms into a system by means of broken or corroded piping, repair of existing mainlines, installation of new mains, back siphonage, and cross-connections, any of which may result in contamination of the water supply. 2013, Reviews of Environmental Contamination and Toxicology, page 80
5. (slang) A principal vein into which a drug can be injected.
   I'm searching for my mainline / I said I couldn't hit it sideways 1968, “Sister Ray”, in Lou Reed (lyrics), White Light/White Heat, performed by The Velvet Underground
6. (computing) The main repository for a software project, from which different versions (forks) may be split off.
7. (chess) Alternative form of main line
   8. ...Qe7! is the mainline and Black unpins with Nc6-d8-e6 […] 2005-11-13, Malcolm Pein, “The Sunday chess column”, in The Daily Telegraph, archived from the original on 2016-07-06