Per′tur‐ba″tion (?), n. [L. perturbatio: cf. F. perturbation.] 1. The act of perturbing, or the state of being perturbed; esp., agitation of mind.
2. (Astron.) 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.