Abscess

An abscess (Latin: abscessus) is a collection of pus (neutrophils) that has accumulated in a cavity formed within a tissue because of an inflammatory process in response to either an infectious process (usually caused by bacteria or parasites) or other foreign materials (e.g., splinters, bullet wounds, or injecting needles). It is a defensive reaction of the tissue to prevent the spread of infectious materials to other parts of the body.