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):

At her husband’s death, a widow may have her marriage portion and inheritance at once and without trouble. She shall pay nothing for her dower, marriage portion, or any inheritance that she and her husband held jointly on the day of his death. She may remain in her husband’s house for forty days after his death, and within this period her dower shall be assigned to her.

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.

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