datum.

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

given this datum, it follows that

Singular of data: A single recorded phenomenon, especially obtained by scientific work.

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.

GD&T tells us that the center of a bolt circle is in fact defined by the locations of the holes themselves, as each is a datum.

A floating reference point, or SLDMB, used to evaluate surface currents in a body of water, and often employed by coastal search and rescue.

To provide missing data points by using a mathematical model to extrapolate values that are outside the range of a measuring device.