Jitter
Variation in timing around an expected schedule, latency or sampling interval rather than a constant shift in the average value.
Timing Variation
Jitter describes variability: packet arrival times, task wake-ups, audio sampling or control-loop execution can fluctuate even when the average interval looks correct.
For real-time systems, bounded variation can matter more than a good mean because deadlines are violated by tail events.
Sources
Scheduler contention, interrupts, GC pauses, network queues, clock-domain differences and buffering can all introduce jitter.
A stable average therefore does not establish deterministic behavior.
Measurement
Report a distribution or worst-case bound appropriate to the system instead of only average latency.