leather vs skin

[keannu]

Do you know the difference between "leather" and "skin" for animals?
I had to figure out the difference in a material, but I lost the part. I'm not sure what was the issue in there,
as far as I remember, "leather" was used for natural skin of some animal, and I said it's wrong as "leather" is only a synthetic one, which I regret.

 

[MikeNewYork]

Leather is the "tanned" hide of an animal, usually a bovid.

See here: http://en.wikipedia.org/wiki/Leather