a usu small body of gas within a liquid or solid
a thin, spherical, usu transparent, film of liquid inflated with air or vapour
a transparent dome
something that resembles a bubble in shape, esp the circle enclosing the words or thoughts of characters in comics
something that lacks firmness or reality, esp an unreliable or speculative scheme
a sound like that of bubbling
[Middle English, prob imitative of the noise of bubbling]