Definition - What does Nyquist Frequency mean?
The Nyquist frequency is a type of sampling frequency that uses signal processing that is defined as “half of the rate” of a discrete signal processing system. It is the highest frequency that can be coded for a particular sampling rate so that the signal can be reconstructed.
The Nyquist frequency is also known as the folding frequency.
Techopedia explains Nyquist Frequency
The Nyquist frequency refers to the point where it is possible to build a visual model of a signal. This goes back to a concept in discrete time sampling called "aliasing." The idea here is that two samples per cycle are needed in order to sufficiently demonstrate a signal. This idea is called the "Nyquist theorem." Developers and engineers look at issues with sampling, including undersampling and oversampling, to try to optimize waveforms and sampling for signal processing efforts.