Datum is, from its Latin origin, a singular form of "data", and may refer to a single item of data.

Singular data point Datum reference, in carpentry, metalworking, needlework, geometric dimensioning and tolerancing Vertical datum, reference surface for vertical positions Geodetic datum, a standard position or level that measurements are taken from in geographic surveying Chart datum, level of water depth on a nautical chart Zero milepost, an origin for travel distances

Publications Datum (magazine), an Austrian monthly magazine Omne Datum Optimum ("Every perfect gift"), a papal bull issued by Pope Innocent II in 1139 endorsing the Knights Templar

Geography Datum Peak, New Zealand Datum (Greece), a city in ancient Macedonia