Leather is material made from animal skin that has been treated and preserved through a process called tanning. Without tanning, animal hides would rot or become stiff and brittle, but tanning transforms them into a strong, flexible material that lasts for years.

People have made leather for thousands of years, using it for shoes, belts, saddles, book covers, and countless other items. A leather jacket feels different from cloth because it's thicker and stiffer, yet it molds to your body over time. Baseball gloves are made from leather because the material is tough enough to catch a fastball without tearing, yet soft enough to form a pocket.

Leather comes primarily from cattle, though people also make it from sheep, goats, pigs, and other animals. The quality varies: some leather is thick and sturdy (like the kind used for work boots), while other leather is thin and supple (like the kind used for fancy gloves).

As an adjective, leather can describe the distinctive smell and texture of this material. When someone describes a room as having a leather smell, they mean that rich, slightly earthy scent that comes from tanned animal hide.