Final answer:
A vesicle, or blister, is a small, raised bump on the skin filled with fluid. It is caused by conditions like impetigo, a bacterial skin infection.
Step-by-step explanation:
A vesicle, also known as a blister, is a small, raised bump on the skin that is filled with fluid. It is an encapsulated sac located just below the upper layers of the skin. Vesicles can be caused by various conditions, such as impetigo, a bacterial skin infection that leads to the formation of fluid-filled blisters.