pinpoint (n.)youdaoicibaDictYouDict[pinpoint 词源字典]
also pin-point, "point of a pin," 1849, from pin (n.) + point (n.). Taken into aeronautics in sense "place identified from the air," hence verb meaning "locate precisely" (1917), which originally was aviators' slang. Related: Pinpointed; pinpointing. As an adjective, "performed with precisional accuracy," 1944, originally of aerial bombing.[pinpoint etymology, pinpoint origin, 英语词源]