Definition of route master in US English:

route master

noun

  • 1A person who is responsible for the route of a procession, race, etc.

  • 2(In form Routemaster) a type of double-decker bus, typically having its engine at the front and an open platform at the rear for passengers to enter or exit (a trademark in the United Kingdom).

Origin

Early 20th century; earliest use found in Sheffield & Rotherham Independent.