The skin of a sheep or goat (and by extension often used more generally to include vellum), prepared for writing on; also used for the bindings of books. Preparation was a lengthy process: once the wool had been removed, the skin was soaked in lime to remove the flesh, then stretched on a frame, scraped with a *lunellum, and treated with chalk to whiten the surface. [< Lat. pergamina = writing material from Pergamum; also Parthica pellis = Parthian skin] -
Dictionary of Medieval Terms and Phrases. Christopher Coredon with Ann Williams.