semaphore

noun

1. an apparatus for conveying information by means of visual signals, as a light whose position may be changed.
2. any of various devices for signaling by changing the position of a light, flag, etc.
3. a system of signaling, especially a system by which a special flag is held in each hand and various positions of the arms indicate specific letters, numbers, etc.

verb (used with or without object), sem·a·phored, sem·a·phor·ing.

4. to signal by semaphore or by some system of flags.

noun

1. an apparatus for conveying information by means of visual signals, as with movable arms or railway signals, flags, etc
2. a system of signalling by holding a flag in each hand and moving the arms to designated positions to denote each letter of the alphabet

verb

3. to signal (information) by means of semaphore

n.“apparatus for signaling,” 1816, probably via French sémaphore, literally “a bearer of signals,” ultimately from Greek sema “sign, signal” (see semantic) + phoros “bearer,” from pherein “to carry” (see infer). Related: Semaphoric (1808).