Purulence

Pus is an exudate, typically white-yellow, yellow, or yellow-brown, formed at the site of inflammation during infections, regardless of cause. An accumulation of pus in an enclosed tissue space is known as an abscess, a visible collection of pus within or beneath the epidermis is known as a pustule, pimple or spot, and a similar collection of pus around a hair follicle, is known as a boil.