PERTURBATION

perturbation |ˌpərtərˈbā sh ən| noun 1 anxiety; mental uneasiness : she sensed her friend's perturbation. • a cause of such anxiety or uneasiness : Frank's atheism was more than a perturbation to Michael. 2 a deviation of a system, moving object, or process from its regular or normal state of path, caused by an outside influence : some minor perturbation in his house's cash flow. • Physics a slight alteration of a physical system, for example of the electrons in an atom, caused by a secondary influence. • Astronomy a minor deviation in the course of a celestial body, caused by the gravitational attraction of a neighboring body. ORIGIN late Middle English : from Latin perturbatio(n-), from the verb perturbare ‘disturb greatly’ (see perturb ).