vesicle

noun

1. A membrane-bound compartment found in a cell.
2. A small bladder-like cell or cavity, as:
3. A small bladder-like cell or cavity, as:
4. A small bladder-like cell or cavity, as:
5. A pocket of embryonic tissue that is the beginning of an organ.
6. A small cavity formed in volcanic rock by entrapment of a gas bubble during solidification.

   “It frequently contains holes, or vesicles, especially nearer the surface of a flow where gas has escaped.”