Leather is a material that's made from animal skin and used to make shoes, bags, furniture covers, and many other things. You might be too hot if you wear your leather pants to the beach.
Most expensive, well-made shoes are made of leather — although it's pliable and easy to shape, it's also extremely strong and long-lasting. To make leather, the skin of an animal is stripped of all fur or hair, and then tanned, or treated to keep it from cracking and drying. The leather collars on early US Marines' uniforms led to their nickname being "leathernecks."