early 14c. (n.), mid-15c. (v.), perhaps from M.Du. bobbel (n.) and/or M.L.G. 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."
A period of wild speculation in which the price of a commodity or stock or an entire market is inflated far beyond its real value. Bubbles are said to “burst” when a general awareness of the folly emerges and the price drops.