In general, a sample is a part of the total, such as one individual or a set of individuals from a population (of people or things), a small piece or amount of something larger, a number of function values of a function, or part of a song. Sampling, then, is the selection of a subset from a larger whole.

It has distinct meanings in:

• probability theory and statistics: sampling (statistics), statistical sample, sample space
• digital signal processing: a sample refers to the value attained from an continuous signal when being converted to a discrete signal.
• music: a sample refers to any sound played back from a digital sampler device based on the principle referred to above.
• environmental science: soil and groundwater sampling and testing for environmental remediation.