os·cil·late [ óssə làyt ](past and past participleos·cil·lat·ed, present participleos·cil·lat·ing, 3rd person present singularos·cil·lates)
verb
Definition:
1. intransitive verb move backward and forward: to swing between two points with a rhythmic motion
2. intransitive verb be indecisive: to be unable to decide which is the better of two positions, points of view, or courses of action
3. transitive and intransitive verb cause something to change predictably: to cause something to produce rhythmic, predictable variations between two extremes, usually within a set period of time, or vary in this way
[Early 18th century. < Latin oscillat-, past participle of oscillare "to swing" < oscillum "swing, mask" (of Bacchus hung as a charm on a tree to swing) < os "mouth, face, head"]