picket (n.)youdaoicibaDictYouDict[picket 词源字典]
1680s, "pointed stake (for defense against cavalry, etc.)," from French piquet "pointed stake," from piquer "to pierce" (see pike (n.2)). Sense of "troops posted to watch for enemy" first recorded 1761; that of "striking workers stationed to prevent others from entering a factory" is from 1867. Picket line is 1856 in the military sense, 1945 of labor strikes.[picket etymology, picket origin, 英语词源]
picket (v.)youdaoicibaDictYouDict
1745, "to enclose with pickets," from picket (n.). The sense in labor strikes, protests, etc., is attested from 1867. Related: Picketed; picketing.