A datum is a single piece of information or a reference point used in various fields, such as geography, engineering, and statistics. In geography, a datum can refer to a base level from which measurements are taken, like sea level. In statistics, it represents a single data point that contributes to a larger dataset. Datums are essential for ensuring accuracy and consistency in measurements and analyses. For example, in mapping, a geodetic datum provides a framework for locating points on the Earth's surface. Understanding datums helps professionals make informed decisions based on reliable data.