A headband is a thing you wear on your head to keep your hair out of your face. It's like a small, stretchy or elastic band made of fabric or plastic. You can pull it over your head, and it fits snugly around your forehead. It can also go behind your ears if you want it to stay in place. You can wear it when you exercise or play sports to keep your hair out of your face, or just to make sure your hair looks neat and tidy. Some people also wear headbands as a fashion accessory, to match their clothes or show off their personality.