1. a single piece of information or fact
Usage: singular form; plural is 'data'
2. a fixed reference point or surface used as a basis for measurement or calculation
Usage: technical; used in surveying, mapping, and engineering

Examples

• Each datum collected in the survey was carefully recorded.
• The researchers analyzed every datum from the experiment.
• In surveying, a datum is established to measure elevation changes.
• The GPS system uses a global datum as its reference frame.
• One datum alone is not enough to draw a conclusion.
• The datum for this map is based on sea level.