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Meaning & use

main line

noun·Everyday

Last updated

UK/ˈmeɪn laɪn/
US/ˈmeɪn laɪn/

Meanings

  1. nouncountable

    the most important railway route between major cities, or a major railway line

    Grammar: Countable; often used with 'the' or 'a': the main line to London, a main line station.

    Patterns

    • the main line between A and B
    • the main line to somewhere
    • a main line station

    The main line between the two cities was closed for repairs.

    We took the main line to Edinburgh instead of the slower coastal route.

    There are frequent trains on the main line during rush hour.

  2. nouncountable

    a principal road or route, especially one that carries heavy traffic

    Grammar: Countable; usually in the phrase 'main line' or 'main lines' for major roads.

    Patterns

    • the main line into a city
    • a main line road

    The main line into the city was blocked by an accident.

    Trucks are not allowed on this main line during the day.

  3. nouncountablemedicalslang

    a major vein used for injecting drugs, especially in medical or informal drug contexts

    Grammar: Countable; usually in the phrase 'the main line'. This sense is technical or slang.

    Patterns

    • inject into the main line
    • use the main line

    The nurse inserted the needle into the main line for the medication.

    In informal drug slang, 'mainlining' means injecting into a major vein.

Word forms

pluralmain lines

Common combinations

main line station
The main line station is a ten-minute walk from here.
main line service
The main line service runs every half hour.
the main line between
The main line between Paris and Lyon is very busy.
main line route
This is the main line route for freight trains.

Synonyms and how they differ

trunk line
More technical; often used for telephone or railway networks, not for roads.
main route
More general; can refer to any kind of road or path, not just railways.

Opposites

branch lineside road

Word family

mainline adjective
Used before a noun: mainline station, mainline service.
mainliner noun
Rare; a person who injects drugs into a main vein.

Commonly confused: main line or mainland?

main line vs mainland

'Mainland' means the main area of land, not a railway line. Do not confuse the spelling.

Practice

The express train to the capital runs on the ___ line.

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