Leather
From Dwarf Fortress Wiki
Leather is the tanned hide of an animal. It can be used to make many things, including clothing, shields, armor, bags, and crafts at the leather works. Because it only overlaps in the use of end products, the leather industry is considered separate from the clothing industry.
Leather armor will be worn by civilians with the hunting labor enabled, or by military dwarves with at least leather armor enabled. Dwarves instructed to wear chain and plate armor will still wear leather if chain and plate armor are unavailable. Leather is significantly lighter than other forms of armor, and thus is less likely to cause encumbrance penalties.
Making leather requires a tannery workshop, a raw hide or skin from an animal, and a dwarf with the 'tanning' skill turned on. Rotten hides or skin cannot be tanned. The human and dwarven caravans also sell various leather hides, in case few animals inhabit the map.
Leather of rare or dangerous animals can be quite valuable.
