A socket is a hollow opening designed to hold something that fits snugly inside it. Your eye socket is the curved space in your skull where your eyeball sits protected. An electrical socket (also called an outlet) is where you plug in a lamp or phone charger, with specially shaped holes that match the prongs on a plug.

Sockets work by creating a secure connection between two things that need to fit together. A lightbulb screws into a socket in a lamp, making an electrical connection that lets it shine. In your body, ball-and-socket joints like your shoulder let your arm swing in wide circles because the round top of your arm bone sits in a cup-shaped socket.

Whether it's holding your eye, connecting electricity, or letting your bones move smoothly, a socket's job is always the same: providing the perfect spot for something important to fit securely into place.