Noun

1. plural: data a single piece of information
2. plural: data a fact known from direct observation
3. plural: data a premise from which conclusions are drawn
4. plural: datums a fixed reference point
   • 2007, Roger F Tomlinson, Thinking about GIS: geographic information system planning for managers

     Datums are another important map aspect related to projection. A datum provides a base reference for measuring locations on Earth's surface.