What term does Rolex use for its self-winding mechanism?

Rolex uses the term “Perpetual” for its self-winding mechanism. The name refers specifically to the company’s automatically winding rotor, which uses the motion of the wearer’s arm to keep the mainspring charged.

Rolex introduced its full-rotor automatic system in 1931. Unlike earlier “bumper” mechanisms, whose weights moved through a limited arc, the Perpetual rotor could turn through 360 degrees. That made winding more efficient and helped establish the Oyster Perpetual name: “Oyster” described the water-resistant case, while “Perpetual” described the automatic winding system.

A common mix-up is “automatic,” which is the general watchmaking term for any self-winding mechanical movement. “Rotor” is the component that moves, not Rolex’s name for the complete system, and “Oyster” refers primarily to the case design. The word Perpetual does not mean the watch runs forever without servicing; it still depends on stored mainspring energy and regular maintenance.