bubble (n.)youdaoicibaDictYouDict[bubble 词源字典]
early 14c., perhaps from Middle Dutch bobbel (n.) and/or Middle Low German bubbeln (v.), all probably of echoic origin. Bubble bath first recorded 1949. Of financial schemes originally in South Sea Bubble (1590s), on notion of "fragile and insubstantial."[bubble etymology, bubble origin, 英语词源]