I keep writing dataset. Is that correct, or should I write data set?

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    dataset for certain datasets; data set for any set for data in general. In specific contexts, a dataset needs to satisfy conditions to qualify as a dataset. Any set of any data can be called a data set, unqualified.
    – Kris
    Jan 12, 2012 at 10:27
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    I note that googling the NIPS website that contains many academic papers with datasets I find that "data set" reports 1.890 results and "dataset" 2.660 results. The same pattern is seen for plural (datasets/data sets). I would suggest using "dataset". Nov 13, 2015 at 14:05

3 Answers 3


As @mmyers notes, dataset does not appear in any dictionaries. However, there are 172 incidences in the Corpus of Contemporary American English, and all but a handful are in the “academic” section, representing formal academic writing. Its lack of appearance in dictionaries is probably because it is a fairly new coinage, the two examples from the Corpus of Historical American English are from 2001. Nothing from before then. Interestingly, the British National Corpus has 51 incidences, dating from the 1980s to the mid 1990s.


Wiktionary says they are equivalent, but neither Merriam-Webster nor Dictionary.com has an entry.

Given that information, I guess I would classify dataset as technical jargon, but it's really not much of a jargon term. Any technical audience would have no problem with it; a non-technical audience should still easily understand its meaning.

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    Is it possible that data set is written dataset for similitude with database? Has database ever been written as data base?
    – apaderno
    Aug 28, 2010 at 21:55
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    @kiamlaluno: Yes, indeed. Database books from the 1980s and back used to spell it "data base" all the time.
    – CesarGon
    Jan 15, 2011 at 18:42
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    so we should use dataset then since that is the future based on evolution of database word
    – adam
    Nov 7, 2017 at 13:24
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    Today there is an entry in Dictionary.com for Data set. Mar 20, 2019 at 17:01

The APA Style Blog comes down firmly on the data set spelling. Although dataset is understandable, two words still seems to be preferred even in academic settings.

  • The IEEE Dictionary (p. 283) agrees with the spelling data set as well. For technology-related technical writing, it is more correct to use the two-word spelling.
    – Zaya
    Sep 27, 2021 at 15:05

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