What is an automatic watch?

In short: A wristwatch that is mechanically self-winding by arm movement.

D. i.e., as long as the watch is worn on the wrist, it does not need to be wound. The energy supply to these mechanical clockworks comes from a rotor that is set in motion by the natural movement of the wrist. As a result of this movement, the spring develops the necessary tension that keeps the mechanism of the clockwork in operation.

Normal wearing of the watch ensures that the clockwork is permanently supplied with the necessary energy.

The watch should spend longer periods of rest - if you do not want to wind it manually - in a watch winder. The mechanical movement prevents the watch from completely discharging and prevents the movement from gumming up.