A clockwork is the inner workings of either a mechanical clock or a device that operates in a similar fashion. Specifically, the term refers to a mechanical device utilizing a complex series of gears. One of the earliest known examples of a clockwork mechanism is the Antikythera mechanism, a first century BC geared astrolabe device for calculating star positions, recovered from a Greek shipwreck.
A clockwork motor is a clockwork device mechanically powered by a mainspring, a spiral torsion spring of metal ribbon. Power is stored in the mainspring manually by winding it up, turning a key attached to a ratchet which twists the mainspring tighter. Then the force of the mainspring turns the clockwork's gears, until the stored energy is used up. The adjective wind-up refers to mainspring-powered clockwork devices, which include clocks and watches, kitchen timers, music boxes, and wind-up toys.