The synonym for an automatic watch is a self-winding watch. What does it mean? Well…in these watches is a mainspring that is wound automatically as a result of the natural motion of the wearer. Running, swimming, walking… every motion is good to let the eccentric weight turning on its pivot which makes sure your watch gets the energy needed to run all day. If the watch is worn all day, everyday, then manually winding is unnecessary. Then the energy from the mainspring powers the watch movement until it runs down, requiring the spring to be wound again.
If a mechanical watch is neither self-winding nor electrically driven, it is called a manual watch. The intention is to manually wind the watch by turning the crown on the side of the watch. But fortunately these days most mechanical watches are self-winding.