What is "oversample"

n. (context statistics English) An additional sample of a subpopulation, above and beyond the portion of a main sample that already belongs to that subpopulation. vb. 1 (context statistics English) To sample additional members of a subpopulation, above and beyond the members included in the main sample. 2 (context systems English) To sample a signal at a frequency well above its Nyquist rate.