n.
Pronunciation: ˌ p ə r-t ə r- ' b ā -sh ə n, ˌ p ə r- ˌ t ə r-
Function: noun
Date: 14th century
1 : the action of perturbing : the state of being perturbed
2 : a disturbance of motion, course, arrangement, or state of equilibrium especially : a disturbance of the regular and usually elliptical course of motion of a celestial body that is produced by some force additional to that which causes its regular motion
– per · tur · ba · tion · al \ -shn ə l, -sh ə -n ə l \ adjective