Synchronism

1. The state of being synchronous.

2. For repetitive events with the same, multiple, or submultiple repetition rates, a relationship among the events such that a significant instant[?] of one event bears a fixed time relationship to a corresponding instant in another event.

Note: Synchronism is maintained when there is a fixed, i.e. , constant, phase relationship among the group of repetitive events.

3. The simultaneous occurrence of two or more events at the same instant on the same coordinated time scale[?].

Source: from Federal Standard 1037C and from MIL-STD-188