a self-winding watch

A movement that is all mechanical and requires no winding because the rotor (part of the automatic mechanism) winds the mainspring by the movement of the wearer's arm. Most mechanical movements are accurate within one minute each day and have reserve power when not worn of at least 24 hours. Often used interchangeably with the word caliber.

Self-winding watch whose movement is mechanical. A weight (the rotor) turns by the motion of your arm and winds the mainspring. The energy generated by the movement is transferred into mechanical energy that creates the movement. These watches can be shaken or manually wound if the power reserve runs out.

See 'Automatic' above