semaphore
noun /ˈseməfɔː(r)/
/ˈseməfɔːr/
[uncountable]- a system for sending signals in which you hold your arms or two flags in particular positions to represent different letters of the alphabet
信号标；旗语 词源early 19th cent. (denoting a signalling apparatus): from French sémaphore, formed irregularly from Greek sēma ‘sign’ + -phoros.