/ ˈseməfɔː(r); NAmE / noun , verb
■ noun
[ U ] a system for sending signals in which you hold your arms or two flags in particular positions to represent different letters of the alphabet
■ verb
[ v , vn , v that ] to send a message to sb by semaphore or a similar system of signals
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WORD ORIGIN
early 19th cent. (denoting a signalling apparatus): from French sémaphore , formed irregularly from Greek sēma sign + -phoros .