oscillation

Short definition from Wiktionary

Noun

1. 1
   the act of oscillating or the state of being oscillated
2. 2
   a regular periodic fluctuation in value about some mean
3. 3
   a single such cycle
4. 4
   (of a function) defined for each point x in the domain of the function by inf diam(f(U))∣Uisaneighborhoodofx, and describes the difference (possibly ∞) between the limit superior and limit inferior of the function near that point.