# What Is Time? Time is the ordering of persistent flow, counted by recurrence. The later configuration is not created from nothing. It is the same continuous energy, rotating other parts of its extent into present registration. A stable flow registers change by continuing to reconfigure. When records of that reconfiguration recur, the recurrence can be counted. Any recurrent pattern of flow can therefore serve as a clock. Time is the count of such recurrent steps. In this framework, the coordinate $t$ in the equations labels ordered registrations of the changing present. Physical time is the operational order of change.