A writing support material that derives its name from Pergamon (Bergama in modern Turkey), an early production center. The term is often used generically to denote animal skin prepared to receive writing, although it is more correctly applied only to sheep and goat skin, with the term vellum reserved for calfskin. Uterine vellum, the skin of stillborn or very young calves, is characterized by its small size and particularly fine, white appearance; however, it was rarely used.