Pronunciation: (pûr"tur-bā'shun),[key] —n. 1. the act of perturbing.
2. the state of being perturbed.
3. mental disquiet, disturbance, or agitation.
4. a cause of mental disquiet, disturbance, or agitation.
5. Astron.deviation of a celestial body from a regular orbit about its primary, caused by the presence of one or more other bodies that act upon the celestial body.