The Universe of Discourse

Mystery of the quincunx's missing quincunx

A quincunx is the X-shaped pattern of pips on the #5 face of a die.

It's so-called because the Romans had a common copper coin called an as, and it was divided (monetarily, not physically) into twelve uncia. There was a bronze coin worth five uncia called a quīncunx, which is a contraction of quīnque (“five”) + uncia, and the coin had that pattern of dots on it to indicate its value.

Uncia generally meant a twelfth of something. It was not just a twelfth of an as, but also a twelfth of a pound , which is where we get the word “ounce”, and a twelfth of a foot, which is where we get the word “inch”.

The story I always heard about the connection between the coin and the X-shaped pattern of dots was the one that is told by Wikipedia:

Its value was sometimes represented by a pattern of five dots arranged at the corners and the center of a square, like the pips of a die. So, this pattern also came to be called quincunx.

Or the Big Dictionary:

… [from a] coin of this value (occasionally marked with a pattern resembling the five spots on a dice cube),…

But today I did Google image search for qunicunxes. And while most had five dots, I found not even one that had the dots arranged in an X pattern.

(I believe the heads here are Minerva, goddess of wisdom. The owl is also associated with Minerva.)

Where's the quincunx that actually has a quincuncial arrangement of dots? Nowhere to be found, it seems. But everyone says it, so it must be true.

Addenda

• The first common use of “quincunx” as an English word was to refer to trees that were planted in a quincuncial pattern, although not necessarily in groups of exactly five, in which each square of four trees had a fifth at its center.

• Similarly, the Galton Box, has a quincuncial arrangement of little pegs. Galton himself called it a “quincunx”.

• The OED also offers this fascinating aside:

  Latin quincunx occurs earlier in an English context. Compare the following use apparently with reference to a v-shaped figure:

  1545 Decusis, tenne hole partes or ten Asses...It is also a fourme in any thynge representyng the letter, X, whiche parted in the middel, maketh an other figure called Quincunx, V.

  which shows that for someone, a quincuncial shape was a V and not an X, presumably because V is the Roman numeral for five.

  A decussis was a coin worth not ten uncia but ten asses, and it did indeed have an X on the front. A five-as coin was a quincussis and it had a V. I wonder if the author was confused?

  The source is Bibliotheca Eliotæ. The OED does not provide a page number.

• It wasn't until after I published this that I realized that today's date was the extremely quincuncial 2025-05-25. I thank the gods of chance and fortune for this little gift.

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