bubble

A spherically contained volume of air or other gas, especially one made from soapy liquid.

A small spherical cavity in a solid material.

"bubbles in window glass, or in a lens"

(by extension) Anything resembling a hollow sphere.

To produce bubbles, to rise up in bubbles (such as in foods cooking or liquids boiling).

To churn or foment, as if wishing to rise to the surface.

"Rage bubbled inside him."

To rise through a medium or system, similar to the way that bubbles rise in liquid.