main line

• Línea o ruta principal y más importante, como una vía de ferrocarril central, un cable telefónico o de internet troncal, o una vena de gran calibre usada para administrar drogas por vía intravenosa.

A primary or most important route, channel, or connection, such as a major railway line, a principal telephone or data cable, or a key vein for intravenous drug injection.

1. Primary railway routeB1formal

   The principal railway route connecting major cities or regions.

   Línea principal

   • The main line from London to Edinburgh is very busy.
   • Trains on the main line run every hour.
   • The main line was closed for repairs last weekend.

2. Primary or most important partB2formal

   The central or most important aspect of something, such as a business, argument, or system.

   línea principal

   • The main line of their argument is that taxes are too high.
   • The company's main line of business is software development.
   • The main line of the story focuses on the hero's journey.

3. Intravenous drug injectionC2slang

   Slang term for injecting a drug directly into a vein.

   inyección intravenosa de droga

   • He was caught using the main line to inject heroin.
   • The clinic offers help for those addicted to main line drugs.
   • Main line use carries a high risk of infection.