If a function f(t) contains no frequencies higher than W cps, it is completely determined by giving its ordinates at a series of points spaced 1/2 W seconds apart. This is a fact which is common knowledge in the communication art.
—C. Shannon 
“Sampling” refers to both the process of drawing discrete measurements from a signal and the representation of a signal using discrete numbers. It is helpful in computational sensor design and analysis to articulate distinctions between the various roles of sampling:
Hard separations between sampling categories are difficult and unnecessary. For example, there is no magic transition point between measurement and analysis samples in the train of signal filtering, digitization, and readout. Similarly, analysis samples themselves are often presented in raw form as display samples. In the context of system ...