Oscillation/ˌɑːsɪˈleɪʃn/ Definition 1 of 5Pro Tip 1/2Physical movement Refers to something that physically moves side to side or up and down repetitively. The oscillation of a swing set is soothing to some people. Pro Tip 2/2Regular motion The movement is not random but follows a predictable path and frequency. The oscillation of a metronome helps musicians keep a steady tempo.