vesicle science definition

1. A small fluid-filled sac in the body.
2. A membrane-bound sac in eukaryotic cells that stores or transports the products of metabolism in the cell and is sometimes the site for the breaking down of metabolic wastes. Vesicles bulge out and break off from the endoplasmic reticulum and the Golgi apparatus. Vesicles get their energy for mobility from ATP. Lysosomes and peroxisomes are vesicles.
3. A small cavity formed in volcanic rock by entrapment of a gas bubble during solidification.

Related Forms:

• vesicular vesicular adjective