Meaning

noun a hollow globule of gas (e.g., air or carbon dioxide)

noun a speculative scheme that depends on unstable factors that the planner cannot control

noun an impracticable and illusory idea

originPartly imitative, also influenced by burble. Compare Middle Dutch bobbe (“bubble”) > Dutch bubbel (“bubble”), Low German bubbel (“bubble”), Danish boble (“bubble”), Swedish bubbla (“bubble”). The word was first used in its economic sense in association with the collapse of the South Sea Company in 1720, based on the metaphor of an inflated soap bubble bursting.

Etymology from Wiktionary, CC BY-SA 3.0