Vellum n. : A fine kind of parchment, usually made from calfskin, and rendered clear and white, -- used as for writing upon, and for binding books.

Example:
How can I flatten rolled up Vellum paper?

Taxonomy
vellum, Limp vellum, drawing, skin, paper, parchment, blueprints, relative humidity, split skin, free encyclopedia, diplomas, synthetic, sizes, preservation, paper drawings, velin, mammal, calf.

Defination from the web:
vellum deed with seal tag dated 1638. ... There is some confusion about the relationship between the words vellum and parchment. In Europe, from Roman times, the term vellum was used for the best quality of prepared skin, regardless of the animal from which the hide was ...