A datum is a mathematical description of the earth's shape and orientation. Because the earth's shape is not uniform, there are many different local datums used in different parts of the world. These local datums provide a close approximation to the earth's surface in a particular area.
Each Earth coordinate system uses a specific datum to approximate the earth's surface. If two coordinate systems use different datums, then MapInfo Pro must perform a datum transformation when it converts coordinates from one coordinate system to the other. MapInfo Pro uses the Bursa-Wolfe datum transformation method, which is generally accurate to within 10 meters. (When MapInfo Pro converts between two coordinate systems that use the same datum, no datum transformation is performed, and the results are generally accurate to within 0.1 meter.)