1. The act of perturbing, or the state of being perturbed; especially, agitation of mind.
2. (Science: astronomy) 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.
Origin: L. Perturbatio: cf. F. Perturbation.