bubble

(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. Synonyms: house of cards. Examples: "His proposal was nothing but a house of cards." "A real estate bubble."

(noun) an impracticable and illusory idea. Example: "He didn't want to burst the newcomer's bubble."

(noun) a dome-shaped covering made of transparent glass or plastic.

(verb) form, produce, or emit bubbles. Example: "The soup was bubbling."

(verb) flow in an irregular current with a bubbling noise. Synonyms: ripple, babble, guggle, burble, gurgle. Example: "Babbling brooks."

(verb) rise in bubbles or as if in bubbles. Example: "Bubble to the surface."

(verb) cause to form bubbles. Example: "Bubble gas through a liquid."

(verb) expel gas from the stomach. Synonyms: burp, belch, eruct. Example: "In china it is polite to burp at the table."