A datum is a statement accepted at face value (a "given").
Data is the plural of datum.
A large class of practically important statements are measurements or observations of a variable.
Such statements may comprise numbers, words, or images.
1 Etymology
The word data is the
plural of Latin datum, neuter past participle of dare, "to give",
hence "something given".
The past participle of "to give" has been used for millennia,
in the sense of a statement accepted at face value;
one of the works of Euclid, circa 300 BC,
was the Dedomena (in Latin, Data).
In discussions of problems in geometry, mathematics, engineering, and so on,
the terms givens and data are used interchangeably.
Such usage is the origin of data as a concept in computer science:
data are numbers, words, images, etc., accepted as they stand.
2 Usage in English
In English,
the word datum is still used in the general sense of "something given",
and more specifically in cartography, geographyGeography is the scientific study of the locational and spatial variation in both physical and human phenomena on Earth. The word derives from the Greek words g ("the Earth") and graphein ("to write," as in "to describe"). Geography is also the title of v, geologyGeology (from Greek γ&eta ge "the earth") and λογος logos "word", "reason")) is the science and study of the Earth, its composition, structure, physical properties, history, and the processes that shape it. Geolog, and Geometric Dimensioning & Tolerancing to mean a reference point, reference line, or reference surface.
The Latin plural data is also used as a plural in English,
but it is also commonly treated as a mass nounIn English, a mass noun is a type of noun that has a singular, but no plural form. Contrast this with count nouns, which denote "things". A noun phrase can refer to one or more of these things. A mass noun denotes stuff or a substance. Stuff, unlike thing and used in the singularWhen used as a simple adjective in English, singular usually means unique. The singular is one of two grammatical numbers in English; the other is the plural . In mathematics singular has a number of meanings A square matrix is called singular if it is no.
For example,
"This is all the data from the experiment".
This usage is inconsistent with the rules of Latin grammar,
which would suggest "These are the data ...",
each measurement or result being a single datum.
However,
given the variety and irregularity of English pluralIn the English language, nouns are inflected for grammatical number—that is, singular or plural. This article discusses the variety of ways in which English plurals are formed. Phonetic transcriptions, given inside slashes, are in SAMPA notation. Regular constructions,
there seem to be no grounds for arguing that data is incorrect as a singular mass noun in English.
3 Uses of data in computing
Raw data are numberA number is an abstract entity used to describe quantity. There are different types of numbers. The most familiar numbers are the whole numbers {0, 1, 2,. denoted by W and the natural numbers {1, 2, 3,. used for counting and denoted by N . If the negatives, charactersFor alternate meanings, see character. In computer terminology, a character is a unit of information that roughly corresponds to a grapheme, or written symbol, of a natural language, such as a letter, numeral, or punctuation mark. The concept also include, imageIn common usage, an image (from Latin imago or picture is an artefact that reproduces the likeness of some subject—usually a physical object or a person. Images may be two-dimensional (e. a photograph) or three dimensional (e. a statue). They are typicalls or other outputs from devices to convert physical quantities into symbols, in a very broad sense. Such data are typically further processed by a human or input into a computer, stored and processed there, or transmitted ( output) to another human or computer. Raw data is a relative term; data processing commonly occurs by stages, and the "processed data" from one stage may be considered the "raw data" of the next.
Mechanical computing devices are classified according to the means by which they represent data. An analog computer represents a datum as a voltage, distance, position, or other physical quantity. A digital computer represents a datum as a sequence of symbols drawn from a fixed alphabet. The most common digital computers use a binary alphabet, that is, an alphabet of two characters, typically denoted "0" and "1". More familiar representations, such as numbers and letters, are then constructed from the binary alphabet.
Some special forms of data are distinguished. A computer program is a collection of data which can be interpreted as instructions. Most computer languages make a distinction between programs and the other data on which programs operate, but in some languages, notably Lisp and similar languages, programs are essentially indistinguishable from other data. It is also useful to distinguish metadata, that is, a description of other data. The prototypical example of metadata is the library catalog, which is a description of the contents of books.
