quadragon

Doesn’t appear to be a ‘real’ word, but I found this:

What is trigonometry?
We can answer this by looking at the origin of the word trigonometry.
Words ending with -metry are to do with measuring (from the Greek word metron meaning “measurement”). (What do you think that thermometry measures? What about geometry? Can you think of any more words ending with -metry?)
Also, the -gon part comes from the Greek gonia) meaning angle. It is derived from the Greek word for “knee” which is gony.
The prefix tri- is to do with three as in tricycle (a three-wheeled cycle), trio (three people), trident (a three-pronged fork).
Similarly, quad means 4, pent 5 and hex six as in the following:

• a (five-sided and) five-angled shape is a penta-gon meaning literally five-angles and
• a six angled one is called a hexa-gon then we could call
• a four-angled shape a quadragon
  (but we don’t – using the word quadrilateral instead which means “four-sided“) and
• a three-angled shape would be a tria-gon
  (but we call it a triangle instead)
• “Trigon” was indeed the old English word for a triangle.

So trigonon means “three-angled” or, as we would now say in English, “tri-angular” and hence we have tri-gonia-metria meaning “the measurement of triangles”.
With thanks to proteus of softnet for this information.

Source: Two-dimensional Geometry and the Golden section.

And since there were forty windows (a number truly perfect, derived from from the decupling of the quadragon, as if the Ten Commandments had been multiplied by the four cardinal values), forty monks could work at the same time, though at that moment there were perhaps thirty.

Source: The Name of the Rose by Umberto Eco.