Allan Metcalf has a Lingua Franca piece on the word equinox which is mildly amusing but which I wouldn’t bother posting here except for this bit: “So getting back to equinox: The first observation is that there are two exquinoxes (yes, that’s the plural) every year…” My first reaction was “No, that isn’t the plural, what the hell are you talking about?” But of course I’ve learned not to trust first reactions, so I looked it up and confirmed my sense of things: not only is there no mention of such a plural in my various dictionaries (though there is an alternative plural equinoctes), but an Advanced Search of the OED produces the unequivocal “No results found for ‘exquinoxes’.” In other words, this silly form does not occur anywhere in the text, citations, or etymologies of the most comprehensive dictionary of English. So I was about to write an indignant letter to Allan Metcalf saying “What the hell are you talking about?” … but I decided to make one last try and search Google Books, and to my amazement there were pages of results like “The Ouse, or Isis, as Sir Henry Spelman says is its proper name, ‘is remarkable for its extraordinary over-flowing’ at the two Exquinoxes” (1781), “Great atmospherical commotions also excite and exasperate them, and hence they are more obstreperous, and require more care at the period of the exquinoxes than at any other time” (1839), “The port of Tripoli is anything but a safe one, the rottenness of its bottom rendering the anchorage very unstable, especially during the tremendous gales that blow there during the exquinoxes” (1878), “that anyone should have mixed up three arbitrary methods of determining the exquinoxes of a planet” (1902), etc. They’re virtually all from the nineteenth or very early twentieth centuries, but there are recent outliers, e.g. “FE and HE are the group means for vernal and autumnal exquinoxes, respectively” (1973) and “The exact dates of the Vernal and Autumnal Exquinoxes may vary by a day or two” (2001). Does anybody have any idea what might be going on here? How was this misbegotten form invented, and how did people get the idea it was a good thing to keep using?

Update. After all that, it tunrs out that “exquinoxes” was in fact a typo as some commenters suggested, and Prof. Metcalf has asked his editors to correct it. Ah well, we all had fun guessing!


  1. Did you also check the relative frequency of exquinox? Maybe it’s based on a misspelling of the root instead of a malformation of the plural.

  2. Jim (another one) says:

    I am surprised at you, Hat; what is obnoxious about putting an English suffix on an English word? Anything else would be equinoxious. I thought you leaned descriptivist.

  3. I think it’s from a misanalysis of equi-nox as e-*quinox. Since e- is a less common variant of ex- (it mostly occurs in verbs, I think), exquinox is a likely enough development. As for the English plural ending, it’s standard — nobody says equinoctes, though the adjective is equinoctial, and the phrase equinoctial gales is common in poetry.

  4. I am surprised at you, Hat; what is obnoxious about putting an English suffix on an English word? Anything else would be equinoxious. I thought you leaned descriptivist.

    Go back and read the post again, carefully. Or just the title, actually. I think you’ve missed the problem.

  5. Did you also check the relative frequency of exquinox? Maybe it’s based on a misspelling of the root instead of a malformation of the plural.

    I didn’t, but he didn’t say the word was exquinox and the plural exquinoxes, which would have been bizarre but at least consistent; he said “exquinoxes” was the plural of the word equinox.

  6. J.W. Brewer says:

    The actual Latin plural (according to a moment’s googling, so perhaps cum grano salis) appears to be (in nom. and acc.) “aequinoctia,” since the nom. sg. is “aequinoctium.” (And of course “-noctium/-noctia” would not be quite so affected or high-falutin’ in English as “-nox/-noctes” might be.)

  7. I had the same reaction as Jim (another one), but then at the latter half of the post I saw it. Feels like a strange kind of consonantal umlaut.

  8. His main point doesn’t really make sense to me, either. Since (as he says) we usually reckon by days rather than nights, it makes sense that an equinox treats day as the default and compares the length of the night to it, rather than treating night as the default and comparing the length of the day to it. (I mean, it might make the most sense to explicitly list both and say that they’re equal — equinoctidies or something, I dunno — but his suggested equidies makes the least sense to me.)

  9. Maybe the motivation is that the changing length of the night is what’s most salient to the lives of diurnal organisms like us.

  10. I think we should start forming all pluxrals in this way.

  11. Jim (another one) says:

    “Go back and read the post again, carefully. Or just the title, actually. I think you’ve missed the problem.”

    I was just cracking on your initial reaction.

  12. Oh, I see. But I’m descriptivist about actual forms used by real people, not bizarre and apparently invented-from-whole-cloth monstrosities (or monxstrosity) like “exquinoxes.”

  13. @Ran:
    If you think like an ancient astronomer more interested in nighttime phenomena than in daytime phenomena, aequinoctium is perfectly natural.

    It’s a sort of nerdview.

  14. Doesn’t Latin dies have the same ambiguity as English day, referring to both a 24-hour period and the part of that period when it’s light? It seems like that weighs against equidies also.

  15. If you think like an ancient astronomer more interested in nighttime phenomena than in daytime phenomena, aequinoctium is perfectly natural.

    Looks like Slavic languages, as well as Danish and Welsh, use half-calques meaning “equal DAY” rather than “equal night”; and a whole number of languages uses different semi-calquing including words both for day and night.

    No detailed explanations (or eplanations?) for your puzzle, LH, but the word exquinox looks really ubixquitous

  16. German avoids these difficulties neatly, bluntly with [die] Tagundnachtgleiche, or Äquinoktium. The plural is [die] Tagundnachtgleichen. It’s a very unusual construction, I guess by analogy with dieselbe, die gleiche.

    I wonder what the background is to the die (note I do not say “feminine gender”). Was “[die] Zeit” pressing on someone’s synapses when the word was born ?

  17. I increasingly hear the term “equilux” instead of “equinox,” but it is still extremely uncommon (and the usage may be largely limited to people involved in the physical sciences). However, the term “equilux” also appears to be a term of art in electrical engineering, which I was wholly unfamiliar with until I searched for it just now. (It is striking how different the terminology used by electrical engineers can be from the terminology used by physicists to discuss the same concepts.)

    As for “exquinox(es),” I think it’s just a typo. I don’t know if I have ever produced this particularly one, but I know that I have a tendency to introduce extraneous “x” characters between an initial “e” and an unvoiced stop in writing and typing.

  18. Trond Engen says:

    The Danish jævndøgn means “equal + 24 hour period”. There’s some disagreement over whether døgn always meant “24 h period” or if its just a variant form of West Norse døgr, which used to mean “day or night = 12 h period”. I think I’ve seen it explained as a dual, but Bjorvand & Lindeman don’t go into that.

    I think aequi in the Latin compound should be understood as “same as”, used to form an adjective “same-as-night”.

  19. As for “exquinox(es),” I think it’s just a typo.

    If it were in one or two texts, maybe it would be a typo. Not in all those texts, and especially not if someone is calling it the standard plural.

  20. David Marjanović says:

    I’m reminded of how the Colosseum had become Colysaeus by the time of Bede…

    I wonder what the background is to the die (note I do not say “feminine gender”). Was “[die] Zeit” pressing on someone’s synapses when the word was born ?

    Somewhere in Germany, nominalization with feminine -e is productive: die Denke, die Spreche, die Schreibe = the way of thinking/speaking/writing. Die Gleiche meaning “equality” sounds… actually less abstruse to me than the other examples, but I’m too tired to figure out quite why.

    (Alien to me, ultimately because the southeastern dialects have undergone a few extra rounds of apocope.)

  21. Trond Engen says:

    the southeastern dialects have undergone a few extra rounds of apocope

    Careful pronunciation of unstressed syllables is the backbone of civilization. Apocopalypse is looming!

    (With apocologies to my son.)

  22. My takeaway is maybe the OED is less useful than Google Books these days.

  23. The OED can’t be expected to include every single variant form that has ever existed, although this one seems to occur often enough it may be added when they update the entry. The significance of its absence from the OED has nothing to do with its actual existence; it is that it decisively refutes the idea that exquinoxes is “the plural” of equinox.

  24. January First-of-May says:

    Russian равноденствие pretty definitely refers to the day (as in daytime, день, not the 24 hour period, сутки – though the former is commonly used to mean the latter).

    I also thought that exquinoxes was a typo, but it is strange that so many texts would have made the same typo in this already fairly uncommon word (and if it was a typo, it would’ve been more common in 20th century texts, not 19th, anyway).

  25. David, in Grimm I find entries for [der] Gleichtag and [die] Gleichnacht. Tagundnachtgleiche is mentioned there, but doesn’t have an entry for itself. There is an entry for Gleich, Gleiche as noun, “vor allem als begriff der rechtssprache …, in der form des substantivierten adjektivs, seit der mitte des 14. jh., namentlich auf nd. boden, reich bezeugt“, with the example eyn genuge und gleiche tuen (1400).

  26. Checked Google Books. The earliest mention of this typo is in Dictionnaire universel, contenant généralement tous les mots françois tant vieux que modernes, & les termes des sciences et des arts. Tome 2 by Messire Antoine Furetière, abbé de Chalivoy, de l’Académie Françoise, published posthumously in Rotterdam in 1690.

    English authors simply copied this typo, because Académie Françoise is the ultimate authority and can’t be wrong!

  27. I see also plenty of the singular “exquinox” in Google Books, mostly nineteenth century, all of which appear unknowing (none emphasize “that’s actually the correct spelling, did you know”), so I think that’s a reasonably common typo.

    It’s also on the web, sometimes looking like a deliberate coinage or a pun. (As a nightclub a portmanteau with “exquisite” and “nox”?)

    No idea where the singular/plural idea comes from though!

    ETA: Oliver Wendell Holmes uses “exquinox”, at least as printed. Could it possibly have been considered correct and well-known enough to need no comment?

  28. I was staring at the word and for ages just didn’t see that first ‘x’ – sorry for being dim! It’s fun to discover such things (trying to catch up quickly after being away for a week or so). For me it’s never been other than ‘equinox’ and ‘equinoxes’, with a grin when someone said or wrote ‘equinoctes’. Don’t think anyone says ‘equinoct’… or, rather, ‘equinocte’.

  29. David Marjanović says:


    I’m so stealing this.

  30. It occurs to me that maybe it’s a typo in the Metcalf piece — that he meant to write “there are two equinoxes (yes, that’s the plural) every year,” implying “in case you thought the falsely Latinate equinoctes was the plural,” but was betrayed by the typesetter… or, since this is an online essay, by his own fat fingers… and he wound up inadvertently making the silly claim I spent time and effort demolishing. In which case, I apologize to Prof. Metcalf — but I don’t think that’s a very likely scenario.

  31. @languagehat: That still seems a more likely scenario than the alternatives.

  32. Well, I’ve written to him, so hopefully we’ll learn the answer.

  33. My tongue stumbles over that word: it wants to say apocopocalypse.

  34. Just say “pocopalypse.”

  35. Augustus Maria von und zu Blattburg says:

    Surely the true Engleesh plural is ‘equinoxen’?

  36. My immediate thought was of a teacher of mine who consistently said ‘expecially’ (he also said ‘flustrated’, but that’s another matter.) In other words, that’s the process that John Cowan mentions, of regularizing the initial e- to ex-. I don’t think any etymologizing is involved, though.

  37. I’ve heard ‘excape’ quite a bit here in Massachusetts, to the point that I wonder if there might be a regional aspect to it – though maybe it’s equally common elsewhere.

  38. Trond Engen says:


    Spring equinox

  39. David Marjanović says:

    regularizing the initial e- to ex-

    Expecially, and the infamous expresso, look to me more like initial es- is hypercorrected to ex-.

  40. You’re right, no doubt. That should apply to excape as well.

  41. Stephen C. Carlson says:

    the infamous expresso: If I’m ever caught using this spelling, I’ll just claim I’m using the French form.

  42. Apparently the choice of equal-nychthemeron in Danish is not original.

    Jævn-døgn, et ell. † en (Moth.​J77. Holb. Kh.1022).
    1) (ænyd. d. s., oldn. jafndœgr, sml. oldn. jafnnætti, oht. ebannahti samt lat. æquinoctium)

    I read that to say that the Norse used either.


    From the Metcalf piece:

    Of the gloomy pre-Conquest era, when Unferth measured Beowulf and Breca’s swimming contest in nights (and for that matter measured years in winters), only a slight vestige remains, the fortnight.

    And “sennight” for people who’ve read Burgess.

    How does it work in Judaism? The new day begins at sunset, but is the counting by days or by nights?

  43. David Marjanović says:

    oht. ebannahti

    Oh! Literally “even-nights”, when day and night are even.

  44. Tfw you realize that jævn = eben doesn’t feel remarkable anymore. Like jord = Erde and so on.

  45. Trond Engen says:

    Oh, I didn’t mean to say that jævndøgn is unique to Danish. But I wasn’t aware of the other O.N. word jafnnætti. Both that and jafndœgri are neuters formed from a dative singular of the root noun. That would seem to suggest an origin as an adjective or adjectival phrase “to/for/with equal night”.

    It’s interesting that Danish Da. døgn apparently could be common gender. That might support an origin as a plural (or dual) formation from dœgr. But my ON dictionary has it as a neuter and glossed as “= dœgr”.

    Also, my dictionary has jafndœgrishringr “equator”.

  46. Døgn is neuter. You’d rarely mark jævndøgn for definiteness or give it an article, it feels more like a name, but it’s a neuter too if you want to.

    I wonder if it’s actually one of those ancient -r/n neuters like water and fire, or if dœgr just developed a variant dœgn in ON times.

  47. Trond Engen says:

    Yeah, døgn is neuter, but Sili’s quote from ODS says it wasn’t always always thus.

    I think the -r/-n neuter is tuled out by the umlaut vowel œ, which needs a syncopated i.

  48. “Well, it’s a Germanic language; obviously we can Thule that out.”

  49. Trond Engen says:

    Hey, I’m no Thule!

  50. I suppose something can be tuled out when it is out in the tulies.

  51. That’s tules.

  52. (damn, cut off by the timer)

    And while I am at it, boondocks is < Tagalog bundok ‘mountain’.

  53. OK, I heard back from Prof. Metcalf, and “exquinoxes” was in fact a typo (which I urged him to have them correct). My congratulations to those of you who suggested as much, and as I wrote him, I’m even more boggled at all the examples of “exquinoxes” I found in Google Books.

  54. Why would he write “(yes, that’s the plural)” after an ordinary plural?

  55. Doubtless to deflect the falsely learnèd form equinoctes, from people who write virii as the plural of virus.

  56. OK, time to ask: How do people who write virii think it’s pronounced? /ˈvɑɪ.ɾɑɪ.ɑɪ/? /ˈviː.ɾiː.ɑɪ/?

    At least the Danish latinate vira /’viːʁɒ̰ː/ has an excuse in virus being a first declension neuter, but I don’t think it’s attested.

  57. Latin virus ‘poison, venom, slime, gunk’ can be either second declension (o-stem) or less commonly fourth declension (u-stem). It is neuter, as you say, but is a mass noun and so has no plural.

  58. Well, unless you’re speaking in New Latin about viruses. As Lars indicates, vira, virorum seems to be the most popular choice.

  59. @Lars: My pronunciation is /ˈvɑɪ.ɾɑɪ/, when I read the word, although I would personally only write “viruses.”

  60. I think I’d say /ˈvɑɪ.ɾiː.ɑɪ/, parallel to radii, but I’ve never understood what people are thinking with virii (viri I could understand).

  61. David Marjanović says:

    Lots of people in the English-speaking world believe -ii is a Latin plural ending. This goes so far that penii, meant to be the plural of penis, has 172,000 ghits!

    (The first is the Urban Dictionary: “penii. A word made up by people uneducated in the ways of etymology. NOT THE PLURAL OF PENIS. The rule with aplural form with an I is derived from latin …”)

  62. Are people in the US and/or British school system exposed to radii in maths class? That would explain some of the misunderstanding.

    @JC, yes, second declension. My mind just lumps first and second as ‘thematic,’ they are so similar. More so in Classical than Old Latin, but I think that only proves that the speakers lumped them too.

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