Main Entry: per·tur·ba·tion

Pronunciation: \ˌpər-tər-ˈbā-shən, ˌpər-ˌtər-\

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 \-shnəl, -shə-n^əl\ adjective