from The American Heritage® Dictionary of the English Language, 4th Edition

  • n. A fact or proposition used to draw a conclusion or make a decision. See Usage Note at data.
  • n. A point, line, or surface used as a reference, as in surveying, mapping, or geology.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. A measurement of something on a scale understood by both the recorder (a person or device) and the reader (another person or device). The scale is arbitrarily defined, such as from 1 to 10 by ones, 1 to 100 by 0.1, or simply true or false, on or off, yes, no, or maybe, etc.
  • n. (philosophy) A fact known from direct observation.
  • n. (philosophy) A premise from which conclusions are drawn.
  • n. (cartography, engineering) A fixed reference point.

from the GNU version of the Collaborative International Dictionary of English

  • n. Something given or admitted; a fact or principle granted; that upon which an inference or an argument is based; -- used chiefly in the plural.
  • n. a single piece of information; a fact; especially a piece of information obtained by observation or experiment; -- used mostly in the plural.
  • n. The quantities or relations which are assumed to be given in any problem.
  • n. a point, line, or level surface used as a reference in measuring elevations.

from The Century Dictionary and Cyclopedia

  • n. A fact given; originally, one of the quantities stated, or one of the geometrical figures supposed constructed, in a mathematical problem, and from which the required magnitude or figure is to be determined.
  • n. A fact either indubitably known or treated as such for the purposes of a particular discussion; a premise.
  • n. A position of reference, by which other positions are defined.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • n. an item of factual information derived from measurement or research


from The American Heritage® Dictionary of the English Language, 4th Edition

Latin, something given, from neuter past participle of dare, to give; see dō- in Indo-European roots.

from Wiktionary, Creative Commons Attribution/Share-Alike License

From Latin datum.


  • Mr. Smith's method of proving that every circle is 3-1/8 diameters is to assume that it is so, -- "if you dislike the term datum, then, by hypothesis, let 8 circumferences be exactly equal to 25 diameters," -- and then to show that every other supposition is thereby made absurd.

    A Budget of Paradoxes, Volume II (of II)

  • Because, according to our assumptions, the average value of a single datum is greater than the marginal value of that datum (remember, aggregation adds value), a consumer will always be willing to sell data at a price a merchant is willing to pay. Privacy Myopia, Economics of

  • Unfortunately, if the marginal value175 to the consumer of a given datum is small, then the value of not disclosing that datum will in most cases be lower than either the cost of negotiating a confidentiality clause (if that option even exists), or the cost of forgoing the entire transaction. Privacy Myopia, Economics of

  • Your name will be just a datum until that datum is lost, at which point you will be nothing.


  • The key datum is marked by the arrow - the concrete rendering of the closed-up opening - which we can see in another picture.

    You thought it was over?

  • The “Greek” word data is the plural of the Latin word datum – a given….

    More Evasion by Thompson « Climate Audit

  • Gee, I wonder which datum is a more relevant measure of the insurance companies’ position on the bill.

    Matthew Yglesias » Health Care Plan Getting More Popular

  • The biggest stone ball, according to the UDG, is right in this area at 13 Q 598163 2284135 (if they were using WGS84 as a datum, which is not mentioned).

    Las Piedras Bola: the great stone balls of Ahualulco

  • Arthur, the orbital elements transmitted by the GPS satellites -- broadcast ephemeris -- are in a realization of the WGS84 datum, which is connected to the solid Earth, i.e, it's an ECEF Earth Centered, Earth Fixed coordinate frame.

    Rabett Run

  • “John A” #214: You call the datum change “implausible”.

    "But They are Very, Very Wrong" « Climate Audit


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  • A datum (plural datums) is a reference from which measurements are made.

    January 4, 2007

  • "Data" is definitely singular. For the plural, try "dati." Or "datas." Or if you're really feeling edgy, "datulumsicles."

    January 3, 2007

  • The singular form of "data" is "piece of data."

    January 2, 2007