**Vellum** is a fine, smooth writing material made from animal skin — traditionally the skin of a young calf, though lamb and kid were used too. The skin is cleaned, soaked, stretched on a frame, scraped thin, and dried under tension. What you get is not leather: it is pale, thin, slightly translucent, and it takes ink beautifully. Before paper became cheap in Europe, this is what important books were written on, which is why thousand-year-old manuscripts still exist and look wonderful — vellum lasts.

Things to know:

- **Vellum vs parchment.** Both are prepared skin. Strictly, *vellum* is from calfskin and is the finer grade; *parchment* is the general word, often from sheep or goat. In everyday use people mix them up freely, and museums often say "parchment" for everything.

- It is **uncountable**: *written on vellum*, *a sheet of vellum*, *bound in vellum*. Not "a vellum."

- **Modern paper vellum.** Today the word is also used for a smooth, slightly cloudy paper — the semi-transparent sheets used in drafting, in fancy invitations, and as book endpapers. No animal involved. If a stationery shop sells you "vellum," this is what you are getting.

- **Bound in vellum** describes an old book whose cover is stiff pale skin, usually creamy-white and a little warped with age.

Register: specialist and historical. It lives in museums, libraries, rare-book shops, art supply shops, and calligraphy. It carries a strong flavour of age, craft, and expense — using the word signals "this is a made-by-hand, precious object."