Vellum

True vellum is a thin specially treated untanned “leather” from calf skin, also known as parchment (high quality parchment from calf skin is called vellum; general quality parchment is made from calf, goat or sheep skin); used for documents and for book bindings; many early books have vellum bindings.

French: Vélin
Italian: Pergamena
Spanish: Pergamino