Your kneecap is the small, round bone at the front of your knee. Its medical name is the patella, but most people just call it the kneecap because that's exactly what it does: it caps your knee like a protective shield.

When you bend your leg to sit down or jump, you can feel your kneecap slide up and down over your knee joint. It protects the joint underneath and helps the powerful muscles in your thigh work more efficiently when you run, kick, or climb. Without kneecaps, simple movements like walking up stairs would be much harder because your leg muscles wouldn't have the leverage they need.

As a verb, to kneecap something means to harm or weaken it so it cannot function well.

Kneecaps are surprisingly tough, but they can get injured. You might bruise or scrape your kneecap when you fall on pavement, or in rare cases, dislocate it (meaning it gets knocked out of place). Athletes who play sports like basketball or soccer sometimes wear knee pads to protect their kneecaps from hard impacts.