runner

Concise Oxford English Dictionary © 2008 Oxford University Press:
runner/ˈrʌnə(r)/

▶noun

• 1 a person or animal that runs.

  ■ a horse that runs in a particular race.

  ■ a messenger, collector, or agent for a bank, bookmaker, or similar.

  ■ an orderly in the army.

• 2 a vehicle or machine that runs in a satisfactory or specified way.

  ■ Brit. informal an idea that has a chance of being accepted.

• 3 a rod, groove, or blade on which something slides.

  ■ a roller for moving a heavy article.

  ■ a ring capable of sliding or being drawn along a strap or rod.

  ■ Nautical a rope in a single block with one end round a tackle block and the other having a hook.

• 4 a shoot which grows along the ground and can take root at points along its length.

  ■ a climbing plant, or one that spreads by means of runners.

• 5 a long, narrow rug or strip of carpet.

• 6 used in names of fast-swimming fish of the jack family, e.g. rainbow runner.

– phrases
do a runner Brit. informal leave hastily, in order to escape or avoid something.