stopgap (n.)youdaoicibaDictYouDict[stopgap 词源字典]
also stop-gap, 1680s, from stop (v.) + gap (n.); the notion probably being of something that plugs a leak, but it may be in part from gap (n.) in a specific military sense "opening or breach in defenses by which attack may be made (1540s). Also as an adjective from 1680s.[stopgap etymology, stopgap origin, 英语词源]