1. To move backward and forward; to vibrate like a pendulum; to swing; to sway.
2. To vary or fluctuate between fixed limits; to act or move in a fickle or fluctuating manner; to change repeatedly, back and forth. The amount of superior families oscillates rather than changes, that is, it fluctuates within fixed limits. (dc Quincey)
Origin: L. Oscillare to swing, fr. Oscillum a swing, a little mask or puppet made to be hung from trees and swing in the wind, prob. Orig, a little mouth, a dim. From os mouth. See Oral, and cf. Osculate.