Final answer:
A pustule is a small, raised bump on the skin that contains pus. It is a type of blister-like lesion that can be caused by various infections.
Step-by-step explanation:
A pustule is a small, raised bump on the skin that contains pus. It is a type of blister-like lesion that can be caused by various infections, such as acne or impetigo. Unlike a cyst or a deep, solid, raised bump, a pustule has a less defined boundary. It is encapsulated sac filled with fluid or semi-solid matter, typically located just below the upper layers of skin.