Semaphore is the use of an apparatus with telegraphy to create a visual signal transmitted over long-distances.

It may refer more specifically to:

  • Flag semaphore
  • Semaphore telegraph, a system of long-distance communication based on towers with moving arms
  • Railway semaphore signal for railway traffic control
  • Traffic semaphore, another name for automotive traffic lights based on their early resemblance to railway semaphores
  • Turning semaphore or trafficators, retractable arms to indicate turns on automobiles from the 1920s to 1950s

Other

  • Semaphore (programming), in computer science, a mechanism for supporting mutual exclusion in concurrent programs
  • Semaphore (software), a continuous integration testing utility
  • Semaphore, South Australia, a historic seaside suburb of Adelaide
  • Semaphore railway line, Adelaide, a closed railway line in South Australia
  • Semaphore Corporation (company), a software and publishing firm that operated from 1982 to 2017
  • Semaphore (album), a 1998 album by Fridge
  • "Semaphore" (song), a 2004 single by the New Zealand band Jakob
  • Semaphore, fictional professor in Cubitus comic strips or Wowser cartoons

See also

  • International maritime signal flags, one system of flag signals representing individual letters of the alphabet in signals to or from ships
  • Semafor (website), news website
  • Telegraphy, the long-distance transmission of written messages without physical transport of written letters