a hollow globule of gas (e.g., air or carbon dioxide)
"The diver watched as he blew a bubble that slowly rose to the surface of the water."
a speculative scheme that depends on unstable factors that the planner cannot control
"his proposal was nothing but a house of cards"
"a real estate bubble"
a dome-shaped covering made of transparent glass or plastic
"The child sat inside the bubble, watching the rain fall against its clear walls."
A spherically contained volume of air or other gas, especially one made from soapy liquid.
"The child blew a large, shimmering bubble that floated gently in the sunlit garden before popping."
In plain English: A bubble is a thin, soapy film of air that floats until it pops.
"She watched her tea until large bubbles rose to the top."
Usage: As a noun, bubble refers specifically to the spherical shape formed by trapped gas within a thin film of liquid. When used metaphorically for social groups, it implies an isolated environment where members share similar views without outside influence.
To produce bubbles, to rise up in bubbles (such as in foods cooking or liquids boiling).
"The pot began to bubble vigorously as the pasta water reached a rolling boil."
In plain English: To bubble means to make small round shapes rise up and break on top of something, usually when it is being heated or mixed with air.
"She bubbled her tea in the microwave to heat it up quickly."
The word is partly imitative and likely influenced by "burble." Its modern economic meaning, referring to a speculative boom that bursts like a soap bubble, first appeared in 1720.