As Ebola rages on, you may be hearing a lot of numbers in the news:

  • 1976, marking the year when the virus was first identified
  • Over 7,000, registering the total number of cases documented
  • Over 3,000, the number of lives the outbreak has claimed
  • 21 days, indicating the disease’s incubation period

But one number you may not realizing you are hearing is 40–an etymological 40, that is.


"Seafaring vessel." Doodle by @andrescalo.
“Seafaring vessel.” Doodle by @andrescalo.

Quarantine is ultimately from quadraginta,  the Latin word for “forty.” But there is more than one “forty” to this story.

Jordan Shipley nicely summarizes the evolving “forties” of quarantine in his Dictionary of Word Origins:

It was applied first, in all likelihood, to the forty day period of Lent; for which the term ‘quadragesima,’ fortieth, has been substituted. Then it was applied to the forty day period in which a widow might remain in the home of her late husband, before relinquishing to the heir. Finally, it was applied to the forty days during which a ship from an infected port, or bearing infection, must wait before landing.

In the first sense, this Lenten quarantine also named the Biblical desert in which Jesus Christ fasted, a central narrative to the Christian tradition of Lent.  As Shipley notes, the Lenten period is now referred to as the Quadragesima (“fortieth”). The second sense is all about the dower, and is, in fact, written into the very Magna Carta (British Library):


These first two meanings of quarantine are considered to have been taken directly from reduced Medieval Latin forms of quadraginta.

The third sense of quarantine, from which we get today’s sense of medical isolation, was “first imposed in 1377 at Ragusa (now Dubrovnik), on ships from Egypt and the East,” Shipley comments in his Discursive Dictionary. Other sources cite quarantine as first appearing in Venice. This quarantine indeed passes, though, from the Italian quarantina giorni, “period of forty days,” with quarantina from quaranta, “forty,” also showing significant reduction of quadraginta‘s consonants.

Forty Forties

The Latin quadraginta is tallied up from quattuor, “four,” and -ginta, “ten times.” Quattuor is turn from the Proto-Indo-European *kwetwer- (“four”), which also gives English four. And the numerical suffix -ginta is from *dekm, responsible for the –ty in in forty (Old English –tig, “group of ten”) and other cardinal numbers. In Old English, forty was feowertigessentially equivalent to the Latin quadraginta.

You are probably familiar with the spiritual numerology of forty, particularly in Abrahamic traditions. To name a mere few: Forty days and forty nights of rain caused the Flood in the Old Testament. Jesus fasted in the desert for forty days. The Prophet Muhammed was said to be forty years old when visited by the archangel Gabriel.

And you are probably familiar with the notion that forty stands in for “a long period of time.” But why the number forty for this? According to the 1915 International Standard Bible Encyclopedia as quoted in the Online Etymology Dictionary:

[T]he number 40 must have been used very frequently by Mesha’s scribe as a round number. It is probably often used in that way in the Bible where it is remarkably frequent, esp. in reference to periods of days or years. … How it came to be so used is not quite certain, but it may have originated, partly at any rate, in the idea that 40 years constituted a generation or the period at the end of which a man attains maturity, an idea common, it would seem, to the Greeks, the Israelites, and the Arabs.

Let’s just hope that we don’t need forty days and forty nights of these current quarantines.

m ∫ r ∫ 

7 thoughts on “quarantine

  1. I wonder how many days a woman had to stay in her tent after childbirth. I bet it was forty. I wonder if that had anything to do with the phases of the moon. I know that we cycle through an entire cycle of the moon in about 30 days.


  2. In Modern Welsh ‘quarantine’ (noun) is “cwarantin” or “cwarantîn” but in the literary language the inherent ‘forty (days)’ sense of quarantine’s Latin etymology ‘quadraginta’ is preserved “deugeinydd (prawf)” – ‘forty day’s proof’. Sometimes deugeinnydd is written as deugeinddydd clearly showing (well, if you understand Welsh) that ‘deugeinddydd’ is formed of two words deugain+dydd (forty+day). Deugain (two times twenty) is the ‘traditional’ vigesimal system, the decimal form would be ‘pedwar deg (four ten) ie. pedwar deng niwrnod (forty days).


  3. This is fascinating:

    1) It’s just after 5am and I’m greeted by “vigesimal.” Beautiful.
    2) For my own edification, what’s a rough pronunciation of “deugeinddydd”?
    3) French, if course, is partially vigesimal. Do you know if this due to continental Celtic influence?


    1. I’m guessing a rough pronunciation would be /dəɪˡgɛnðiːð/ as being from the literary language its a word you’d rarely hear or at least only in restricted use.
      I don’t know whether French’s partial (I want to say ‘vestigial’ for the sake of alliteration!) vigesimal system was influenced by continental Celtic per se or whether the Celtic languages have just retained an older vigesimal system which was in greater use and widespread in many other European languages in antiquity? Just for quick examples in English we have the often touted example from the nursery rhyme ‘four and twenty blackbirds baked in a pie’. “Four score and seven years ago…” from The Gettysburg Address is another historical example and here in Britain our old ‘£sd’ pre-decimalisation (pre-1971) currency was 20/- (shillings) per pound and 12d (pence) per shilling.


      1. This is an excellent comment. “Vestigial vigesimal” sounds like a lost Frank Zappa record.

        I would the word “dozen” and (others word like it) to this mix as a (once) significant non-decimal counting unit displaying more anthropomorphic and less logical origins of numerals in language.


  4. “Vestigial Vigesimal” definitely sounds like a it could be a song title from Scottish electronic music duo ‘Boards of Canada’ as well eg. Chromakey Dreamcoat, Turquoise Hexagon Sun etc.

    The duodecimal ‘dozen’ still lingers on in everyday speech in the UK probably because it’s now ingrained in idiomatic and figurative language. Having grown up with the (British) Imperial system for weights and measures I still remember having to ask for a dozen or half a dozen eggs in the village shop or marketplace before the rise of the supermarkets.


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