In mechanical horology, a remontoire, (from the French remonter, meaning 'to wind') is a small secondary source of power, a weight or spring, which runs the timekeeping mechanism and is itself periodically rewound by the timepiece's main power source, such as a mainspring. It was used in precision clocks and watches to place the source of power closer to the escapement, thereby increasing the accuracy by evening out variations in drive force caused by unevenness of the friction in the geartrain.