PERTURBATION

disruption, perturbation

(noun) the act of causing disorder

perturbation, fluster

(noun) a disposition that is confused or nervous and upset

perturbation, disturbance

(noun) activity that is a malfunction, intrusion, or interruption; “the term ‘distress’ connotes some degree of perturbation and emotional upset”; “he looked around for the source of the disturbance”; “there was a disturbance of neural function”

perturbation

(noun) (physics) a secondary influence on a system that causes it to deviate slightly

disturbance, perturbation, upset

(noun) an unhappy and worried mental state; “there was too much anger and disturbance”; “she didn’t realize the upset she caused me”

Source: WordNet® 3.1

Etymology

Noun

perturbation (countable and uncountable, plural perturbations)

(uncountable) Agitation; the state of being perturbed

(countable) A small change in a physical system, or more broadly any definable system (such as a biological or economic system)

(countable, astronomy, physics) Variation in an orbit due to the influence of external bodies

Source: Wiktionary

Per`tur*ba"tion, n. Etym: [L. perturbatio: cf. F. perturbation.]

1. The act of perturbing, or the state of being perturbed; esp., agitation of mind.

2. (Astron.)

Definition: A disturbance in the regular elliptic or other motion of a heavenly body, produced by some force additional to that which causes its regular motion; as, the perturbations of the planets are caused by their attraction on each other. Newcomb.

Source: Webster’s Unabridged Dictionary 1913 Edition