- A membrane-bound structure within a cell in which materials such as enzymes are transported or stored.
- A sac or cyst, especially one containing fluid.
- A blister of the skin.
- A cavity formed in volcanic rock by entrapment of a gas bubble during solidification.
- A small cavity or sac filled with fluid; esp., a small, round elevation of the skin containing a serous fluid; blister.
- A small, bladderlike sac filled with air or liquid.