Simple Definition of datum
: a single piece of information
Full Definition of datum
1 plural da·ta play \-ə\ : something given or admitted especially as a basis for reasoning or inference
2 plural datums : something used as a basis for calculating or measuring
Usage Discussion of datum
Data leads a life of its own quite independent of datum, of which it was originally the plural. It occurs in two constructions: as a plural noun (like earnings), taking a plural verb and plural modifiers (as these, many, a few) but not cardinal numbers, and serving as a referent for plural pronouns (as they, them); and as an abstract mass noun (like information), taking a singular verb and singular modifiers (as this, much, little), and being referred to by a singular pronoun (it). Both constructions are standard. The plural construction is more common in print, evidently because the house style of several publishers mandates it.
Examples of datum
<let's begin our discussion of this matter with a datum from actual experience>
Origin of datum
Latin, from neuter of datus
First Known Use: 1646
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