While reading an article about history and use of the camera obscura and camera lucida the use of camera obscuras for the plural felt increasingly wrong. (whinge over)

In general when a (foreign) noun-adjective phrase is used in English the noun take the plural (aides-de-camp, adjutants general, etc.)¹. TFD cites "Random House Kernerman Webster's College Dictionary" for the plural camera obscuras, which is also given in wiktionary without citation; no other dictionaries online list a plural.

Of course, camera as an English word derived from the Latin camera = chamber has the plural cameras, but that doesn't mean cameras obscura would be right because in the phrase camera is still Latin. So should we be using camerae obscurae? This is stated in wikipedia without citation. Have I even got the plurals right in Latin? Probably not, I haven't studied Latin for nearly 25 years. Should we semi-anglicise it to cameras obscura?

¹There are many more words and phrases which take the plural in the middle in the answers to this question.

"Which style of Latin plurals should I use?" is relevant but doesn't provide an answer to what we should do in the case of a phrase. I would even say that it might support "cameras obscura" which nothing else does.

  • Given by Wiktionary; RHK Webster's. Commented Jun 2, 2015 at 8:47
  • I was unconvinced by RHK Websters cited through TFD, hence my question (though I abbreviated it differently to you). As for wiktionary (I must admit I didn't check there specifically) with no citation I'm not inclined to treat it as independent of the one I mentioned in the question.
    – Chris H
    Commented Jun 2, 2015 at 8:54
  • 3
    Do whichever or whatever you want. There are no set rules for this. And even if there were you could break them. This isn't French. Are you of the kind that orders three whoppers junior or three whopper juniors? Squirrels to the nuts and nuts to the squirrels. Just don't say octopi.
    – pazzo
    Commented Jun 2, 2015 at 8:59
  • 1
    That's right. @YohannV. Everyone in USA but Italian-Americans call the meal lasagna, which is patently wrong, since it takes more than one lasagna to make lasagne.
    – pazzo
    Commented Jun 2, 2015 at 9:23
  • 2
    @pazzo I'm hungry and angry now !
    – Yohann V.
    Commented Jun 2, 2015 at 9:26

2 Answers 2


From wiktionary :


New Latin, from camera, chamber, + obscura, dark.


camera obscura (plural camera obscuras)

You can find example of usage in wikipedia page :

Most practical camera obscuras use a lens rather than a pinhole (as in a pinhole camera) because it allows a larger aperture, giving a usable brightness while maintaining focus.

This is a book in references :

  1. Smith, Roger. "A Look Into Camera Obscuras". Retrieved 2014-10-23.

There is a website :

Cameraobscuras.com George T Keene builds custom camera obscuras like the Griffith Observatory CO in Los Angeles.

And this is also a category : Camera_obscuras

The funny part is that camera in english came from this.

  • I was editing this into the question at the same time as you were writing your answer -- it copies the unconvincing definition only given in one relatively minor source.
    – Chris H
    Commented Jun 2, 2015 at 9:04
  • @ChrisH Edited my answer.
    – Yohann V.
    Commented Jun 2, 2015 at 9:10
  • You've found a few more sources, but note that the wikipedia article is inconsistent.
    – Chris H
    Commented Jun 2, 2015 at 9:27
  • @ChrisH wiktionary or wikipedia? If you can read, hebrew article is nice
    – Yohann V.
    Commented Jun 2, 2015 at 9:32
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    @ChrisH The term is based on the Latin camera, "(vaulted) chamber or room", and obscura, "darkened" (plural: camerae obscurae). This is Latin as you said. It is not the usage in English. (The other mention is by a french, in a french museum.) Do as you want, but I find wiki totally fine.
    – Yohann V.
    Commented Jun 2, 2015 at 9:44

Your immediate reaction probably arises from other phrases such as court martial and inspector general. The difference is that these phrases are derived from French, and already have plurals associated with them (courts martial and inspectors general). The term camera obscura seems to have originated with Kepler in 1604, and the term spread as a fixed phrase. As a result, in English the plural is formed by simply adding an s to the final word: camera obscuras.

  • Wikipedia credits Kepler but the cited source actually mentions Herschel. Or would make sense for Herschel, who worked in England, to have introduced the term to English; Kepler on the other hand wrote in Latin and lived mainly in German-speaking countries. He may of course have coined the term. I tagged the discrepancy earlier. I reckon I could find a Latin example though I can't think of one off the top of my head.
    – Chris H
    Commented Jun 2, 2015 at 17:43

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