noun Something known or assumed as fact, and is made the basis of reasoning or inference which an intellectual system of any sort (such as knowledge or theoretical framework) is constructed.
a datum of experience
noun Singular of data: A single recorded phenomenon, especially obtained by scientific work.
noun A point, line, plane, or surface with reference to which positions (such as elevations) are measured or indicated. (Examples include a permanent benchmark in leveling or mean sea level in a topographical survey).
A geodetic datum is sometimes also called a benchmark.
noun A floating reference point, or SLDMB, used to evaluate surface currents in a body of water, and often employed by coastal search and rescue.
verb To provide missing data points by using a mathematical model to extrapolate values that are outside the range of a measuring device.