jag (n.1)youdaoicibaDictYouDict[jag 词源字典]
"period of unrestrained activity," 1887, American English, perhaps via intermediate sense of "as much drink as a man can hold" (1670s), from earlier meaning "load of hay or wood" (1590s), of unknown origin. Used in U.S. colloquial speech from 1834 to mean "a quantity, a lot."[jag etymology, jag origin, 英语词源]
jag (n.2)youdaoicibaDictYouDict
"slash or rend in a garment," c. 1400, of unknown origin.