sheepskinn. 
羊毛

, 羊

袄, 羊

纸, 羊


, 羊

毯, (写

羊

纸


)文件, 毕

文凭
sheepskin[ noun ]- tanned skin of a sheep with the fleece left on; used for clothing
<noun.substance>
- skin of a sheep or goat prepared for writing on
<noun.substance>
- a document certifying the successful completion of a course of study
<noun.communication>

Sheepskin \Sheep"skin`\, n.
1. The skin of a sheep; or, leather prepared from it.
2. A diploma; -- so called because usually written or printed
on parchment prepared from the skin of the sheep. [College
Cant]