A rotor is a part that spins around a central point to make something work. The word comes from “rotate,” which means to turn in a circle.

Helicopters use rotors: those long blades on top that spin incredibly fast to lift the aircraft into the air. As the rotor blades slice through the air, they create enough force to pull the entire helicopter upward. Some helicopters have a second, smaller rotor on the tail that keeps the aircraft from spinning in circles.

Electric motors contain rotors too. Inside a fan, blender, or power drill, a rotor spins to make the machine operate. When you turn on a ceiling fan, electricity makes the rotor inside the motor spin, which turns the blades that cool your room.

Wind turbines work the opposite way: their rotors catch the wind and spin, generating electricity rather than using it. Whether a rotor is powered by wind, water, or electricity, the principle is the same: it's the spinning component that converts energy from one form to another. The rotor is what actually moves, while the stator stays still. Together, they make motors and generators work.