The word “data” is an interesting one in that it is frequently misused. Part of the problem stems from a lack of knowledge about whether this word is singular or plural. What is the plural of data? Actually the word data is already plural, and the real question we should ask is, “What is the singular form of the word data?” The singular of data is the word “datum.”
A Little Bit of Latin
The origin of the word datum is from the Latin language. In Latin the noun datum means “something given.” This noun is from the second declension in Latin. This means that the nominative form of nouns that end with –um has a plural form that ends in –a. What all this means is that the plural of datum is data. There is one datum and several data.
Data and Datum
Although some treat the word data as a collective noun referring to a collection of information, most writing in statistics recognizes the origin of the word. A single piece of information is a datum, more than one are data. We speak of “these data” rather than “this data.” One way to dodge this issue is to consider all of the data as a set. Then we can talk about a singular set of data.