Data is a measurement which can be organised to become information.

In English, the word datum refers to "something given". The word data is plural in English, but it is commonly treated as a mass noun and used in the singular. In everyday language, data is a synonym for information. However, in exact science there is a clear distinction between data and information, where data is a measurement that may be disorganised and when the data becomes organised it becomes information.

Raw data are numbers, characters, images or other symbols. They are processed by a human or a computer and stored and processed there or transmitted (output) to another human or computer. "Raw data" is a relative term; data processing commonly occurs in stages, where data processed from one stage may be considered to be the raw data of the next stage.

Computing devices can be classified according to their means of representing data. An analog computer represents a datum as a voltage or other physical quantity. A digital computer represents a datum as a sequence of symbols drawn from a fixed alphabet. Digital computers commony use a binary alphabet (consisting of two characters), typically denoted by "0" and "1". More familiar representations, such as numbers or letters, are then constructed from the binary alphabet.

Data exist in some special forms:

• A computer program is a collection of data which can be interpreted as instructions.
• Metadata are a description of other data.