# mainline

Pronunciation: US/AUS say "MAYN-lyn" /ˈmeɪnˌlaɪn/; UK

## Adjective

1. Being the normal, principal, or standard kind rather than a marginal or alternative one.
   - Simple: Being the usual, most important kind, not a side or minor one.
   - _The festival drew acts from both indie labels and mainline studios._
   - _Her views fell well outside mainline economic thinking at the time._
3. Relating to the principal route or line of a railway.
   - Simple: Belonging to the main railway track between big stations.
   - _Mainline services resumed once the signal fault was fixed._
   - _The town finally got a mainline connection to the capital._
10. Relating to a surface railway, as distinct from an underground, elevated, or light rail system.
   - Simple: Belonging to a normal ground-level railway, not an underground, raised, or light rail one.
   - _Mainline rail connects the suburbs to the city, while the metro serves the center._
   - _The mainline network uses heavier track than the tram lines._
11. Of an opening sequence, forming part of the standard moves considered best play.
   - Simple: Being part of the standard, most-trusted set of chess opening moves.
   - _The mainline variation of the Sicilian runs many moves deep._
   - _Most grandmasters follow the mainline continuation in this position._

## Noun

2. The principal route or line of a railway, carrying the bulk of through traffic.
   - Simple: The main railway track between big stations, used by most trains.
   - _Express services use the mainline, while local trains divert onto branch routes._
   - _Engineers electrified the mainline to allow faster intercity travel._
5. An airline's main operating unit, separate from its regional subsidiaries or codeshare partners.
   - Simple: The main part of an airline that flies its own planes, not its small partner airlines.
   - _The carrier shifted several short routes from the mainline to its regional partners._
   - _Mainline pilots earn considerably more than those at the affiliated regional airlines._
7. The main repository of a software project, from which separate versions, or forks, can be split off.
   - Simple: The main copy of a software project's code, which other versions are made from.
   - _Each fork eventually drifted far from the mainline._
   - _Contributors submit their changes back to the mainline for review._
8. A major vein used for injecting a drug directly into the bloodstream. *(slang)*
   - Simple: A large vein that drugs can be injected into.
   - _Years of injecting had ruined every usable mainline in his arms._
   - _She rolled up her sleeve looking for a mainline._
13. The general body of ordinary inmates in a prison.
   - Simple: The main group of ordinary prisoners in a jail.
   - _After sentencing, she was released into the mainline._
   - _Guards monitor the mainline closely during meal times._
14. The main pipe carrying wastewater from a building to the public sewers or a septic tank.
   - Simple: The main pipe that carries dirty water from a building to the public drains or a septic tank.
   - _Wastewater from every fixture eventually drains into the mainline._
   - _The crew replaced the old clay mainline with PVC pipe._
15. In longline fishing, the central line to which the baited branch lines are attached.
   - Simple: The long central fishing line that the smaller baited lines hang from.
   - _Each baited snood clipped onto the mainline at regular intervals._
   - _The boat set several miles of mainline before dawn._
16. Alternative form of main line. — Alternative form of main line.
   - Simple: Alternative form of main line. It means the standard, best-play set of chess opening moves.
   - _The mainline of the Italian Game leads to sharp tactical play._
   - _Commentators expected the mainline, but he chose a sideline instead._

## Verb

4. To inject a drug straight into a vein. *(slang)*
   - Simple: To put a drug straight into a vein with a needle.
   - _By his twenties he was mainlining whatever he could afford._
   - _Addicts who mainline the drug risk collapsing their veins._
6. In software development, to merge code into a project's main repository rather than keeping it in a separate fork.
   - Simple: To add new code into a project's main version instead of keeping it in a side copy.
   - _Maintainers mainlined the patch after months of review._
   - _The community pushed to mainline the driver into the kernel._
9. To consume something greedily and without restraint. *(colloquial)*
   - Simple: To eat or use something very fast and in large amounts.
   - _Fans mainline the entire series in a single weekend._
   - _He mainlined espresso to finish the report on time._
12. To place a prisoner among the general population of a prison.
   - Simple: To put a prisoner in with the main group of inmates.
   - _Officials chose to mainline the prisoner once the threat assessment cleared him._
   - _The facility mainlined the transfers into general housing the same day._

## Origin

Formed by combining "main" and "line."

Source: DictionaryAI, https://dictionaryai.com/define/mainline (written from Wiktionary data, CC BY-SA 4.0: https://creativecommons.org/licenses/by-sa/4.0/).