An international time standard calculated by atomic clock and incorporating occasional leap seconds to compensate for changes in the rotation of the earth. Coordinated universal time serves as the basis for standard time around the world.
A highly accurate time scale based on time measured by an atomic clock. Because coordinated universal time is unaffected by the gradual slowing of Earth's rotation, leap seconds are added as needed to synchronize it with the sidereal (rotation-based) universal time. Coordinated universal time is used internationally for scientific and technical purposes.