Difference between data and datum
Data, like a lot of technical and academic words, comes from Latin. It used to be considered as a collective singular noun. In formal documents — for scientific or scholarly writing — data is mostly used as the plural of datum.
Yet, for those of a non-scientific background, data is common for both singular and plural use. It’s acceptable to write a sentence as ‘translation data is available on their website.’ Data is a mass noun. Mass nouns denote something that cannot be counted. When you refer to a small piece of data, this may be called datum.
Definition
- Data (mass noun, plural)
- Facts on which a decision is to be based.
- Facts to be processed by a computer.
- Datum (singular noun)
- Item of data
In addition, there are plural forms that do not end in S as listed below.
| Plural | Singular |
|---|---|
| Bacteria | Bacterium |
| Dice | Die / Dice |
| Formulae | Formula |
| Supernovae / Supernovas | Supernova |
| Graffiti | Graffito |
| Candelabra | Candelabrum |
| Data | Datum |
| Media | Medium |
| Opera | Opius |
| Paparazzi | Paparazzo |
| Men | Man |
| Women | Woman |
| Mice | Mouse |
| Referenda | Referendum* |
Source: OED
