Actually, the "sampling rate" is measured in hertz - as the sampling rate used for compact discs is 44.1 kHz (44,100 cycles per second or, samples per second). The sampling rate must be at least twice the maximum frequency to be reproduced.

So for a CD to reproduce audio up to 20 kHz theorectically requires a sampling rate of 40 kHz The actual standard is set at 44.1 kHz.

You are correct regarding sound. But it also applies beyond sound, into other areas of physics.