We know phenomena is a plural whose singular form is phenomenon. However, I have seen frequent of use of phenomena itself as singular, as in 'this is a phenomena ...', 'this phenomena is ...', etc.

This Google Ngram shows such use may also have been present in literature, 'this phenomena' being more frequent.

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How do we explain this discrepancy and suggest that the usage is wrong?

[Edit 1]: Will usage eventually redefine grammar in such cases as 'phenomena' and 'criteria' then? (inspired by @Barrie England 's comment.)

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    "Phenomena" is not the only word that is confused for singular usage, there are many such words. Even though you explain such things and suggest the right word usage, it's difficult to make most of the people follow it. People are used to this confusion from a long time and its difficult to make them unlearn and relearn. A very good question though. en.wikipedia.org/wiki/English_plural#phenomenon
    – Apoorva
    Commented Dec 29, 2011 at 7:18
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    I'm shocked when people of my generation make this mistake given the proper use of the singular in LL Cool J's hit song Something Like A Phenomenon Commented May 17, 2013 at 13:09

2 Answers 2


There is a tendency for the plurals of Latin words to be treated over time as singular in English and eventually to lose their singular forms, changing their meanings in doing so. Agenda, stamina and data are three examples. This doesn’t seem to happen as much with Greek words such as criterion/a. The reason is possibly that such words are more learnèd and less frequent and may be used by people who know and insist on the difference between the singular and plural. However, as far as phenomena is concerned, ‘The Cambridge Guide to English Usage’ reports that there are instances of its singular use as early as the sixteenth century and that there is good corpus evidence that is gaining ground now. Research in Australia in the 1970s, the article continues, showed that most young people there thought of the word as singular. The article concludes that ‘phenomena seems to be consolidating its position for plural uses, apart from extending its influence into the singular' (my emphasis).

  • I guess what you said for Latin words, such as medium (media) and agendum (agenda), apply to Greek words, such as phenomenon (phenomena) and criterion (criteria), as well. Commented Jun 29, 2017 at 8:05

There is indeed considerable, long-standing evidence of the 'incorrect' usage of phenomena as a singular noun, however it is still fundamentally grammatically incorrect, so if one is concerned with grammar (as would suggest by use of this site) I would recommend phenomenon (s.) and phenomena (pl.). Similarly, consider the opposite such as stadium (s.) and stadia (pl.), although perhaps these days it is advisable to consider one's audience before enforcing such pedantry!

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