Tanning is the process of treating skins and hides of animals to produce leather, which is more durable and less susceptible to decomposition. Traditionally, tanning used tannin, an acidic chemical compound from which the tanning process draws its name (tannin is in turn named after an old German word for oak or fir trees, from which the compound was derived). Coloring may occur during tanning. A tannery is the term for a place where the skins are processed.