Plain English Meaning
It describes what happens to the airplane's wobble after a bump or control input. With good dynamic stability, the wobbles shrink and the airplane settles back to steady flight on its own.
Full Definition
The property of an airplane that determines how its motion behaves over time after it has been disturbed from a steady flight condition. An airplane with positive dynamic stability returns to its original condition with oscillations that grow smaller and eventually die out. Neutral dynamic stability produces oscillations that continue at the same size, and negative dynamic stability produces oscillations that grow larger over time.
Context Anchor
Seen in aircraft stability and handling discussions, especially when how an airplane responds after a in , , or .