master clock

A master clock is a central timepiece that controls or synchronizes other clocks, often referred to as slave clocks. This system is particularly useful in large facilities where maintaining a consistent time across multiple locations is crucial.1

In horology, master clock systems can utilize electricity to send signals that advance the hands of distant clocks, ensuring they all display the same time. This technology allows for precise timekeeping across various devices, from tower clocks to smaller indicating dials. The concept of a "slave clock" also applies to astronomical clocks, where auxiliary apparatus handles most of the work to ensure uniform performance.23