Automatic movement refers to a type of watch mechanism that winds itself as the wearer moves. This self-winding feature is made possible by a small rotor inside the watch that spins with the motion of the wrist, converting kinetic energy into potential energy to power the watch. Unlike quartz watches, which rely on batteries, automatic movement watches are powered by mechanical energy. This means they can run indefinitely as long as they are worn regularly. If not worn for a while, they may need to be manually wound to keep accurate time.