n. 上等皮纸, 皮纸文书, 牛皮纸

a. 牛皮纸的

Vellum \Vel"lum\, n. [OE. velim, F. v['e]lin, fr. L. vitulinus
of a calf, fr. vitulus a calf. See {Veal}.]
A fine kind of parchment, usually made from calfskin, and
rendered clear and white, -- used as for writing upon, and
for binding books.

{Vellum cloth}, a fine kind of cotton fabric, made very
transparent, and used as a tracing cloth.