Definition of "mainline" in English

adjective

1. Normal, principal or standard.

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").

verb

1. (slang) To inject (a drug) directly into a vein.

2. (by extension, informal, transitive) To consume voraciously.

3. (computing, transitive) To integrate (code, etc.) into the main repository for a software project, rather than separate forks.

4. (transitive) To include (a prisoner) in the general population of a prison.

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.

3. (fishing) In longline 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.

5. (slang) A principal vein into which a drug can be injected.

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. The general population of a prison.