The distance between the samples should be set to discretize the signals. The distance can be called a Ts cycle of sampling.
Sampling Frequency=1/T_s =f_s
f_s=sampling frequency or sampling rate
The reciprocal of the sampling period is the sampling frequency. This level of sampling can simply be called the Sampling rate. The sampling rate indicates the number of samples taken per second, for a range of finite values.
The sampling rate should be highly regarded for an analog signal to be reconstructed from the digitised signal. The sampling rate should be such that the data in the message signal should not be lost or over-lapped. Therefore a rate, called the Nyquist rate, was set for this.