girth (n.)youdaoicibaDictYouDict[girth 词源字典]
c. 1300, "belt around a horse's body," from Old Norse gjorð "girdle, belt, hoop," from Proto-Germanic *gertu- (cf Gothic gairda "girdle"), from the same source as girdle and gird. Sense of "measurement around an object" first recorded 1640s.[girth etymology, girth origin, 英语词源]