# What are the names for geometric arrangements like 'quincunx'?

A quincunx is a geometric pattern consisting of five points arranged in a cross:

This seems like a very specific name derived from the Latin root for five (quin). Are there other geometric arrangements with similar related names that were derived the same way, or is quincunx unique?

• This really seems like a list request to me--could you possibly rewrite a bit? – simchona Oct 25 '12 at 18:36
• Please clarify what you mean by "geometric arrangements". Are you also specifically looking only for Latin-based words and only mystic symbols? – coleopterist Oct 25 '12 at 19:07
• I’ve found a few interesting ones to go with quincunx: semunce, sextile, semisextile, tetronkion, pentonkion, sequiquadrate. There is also some connection with NAND I am still tracking down. – tchrist Oct 25 '12 at 19:33

I believe that tetractys should match this request.

Tetractys is a triangular figure consisting of ten points arranged in four rows, which is the geometrical representation of the fourth triangular number.

• Tetra- would make it of Greek origin while quin- is Latin. I'm not sure if the OP is particular about this. But it might be worth noting in your answer. Interesting stuff. – coleopterist Oct 25 '12 at 19:00

“Similar related names that were derived the same way” is unfortunately ambiguous, but if you mean are there other geometric arrangements with names formed by prefixing a Latin geometric term with a Latin numeric prefix, the answer is yes. For example, from etymonline, triangle derived “from O.Fr. triangle (13c.), from L. triangulum “triangle,” from neut. of adj. triangulus “three-cornered,” from tri- “three” (see tri-) + angulus “corner, angle”, and quadrangle “from O.Fr. quadrangle (13c.), from L.L. quadrangulum “four-sided figure,” properly neuter of Latin adjective quadrangulus “having four quarters,” from L. quattuor “four” (see four) + angulus “angle”. Pentagon and nonagon also are from Latin. However, pentangle and hexagon are from the Greek.

• Sorry I wasn't more precise. I am aware of the names of geometric figures. I was hoping to get names of geometric arrangements. – nohat Oct 25 '12 at 20:34
• Pentagon looks Greek at both ends – Henry Oct 25 '12 at 21:13
• @Henry, I agree, but the etymonline pentagon entry suggests it arrived in English via Latin. – James Waldby - jwpat7 Oct 25 '12 at 22:39
• @nohat, a geometric arrangement consists of lines (or hyperplanes), not of points. Points form geometric configurations, not arrangements. See sections 1.1 and 1.3 of Edelsbrunner's Algorithms in Combinatorial Geometry. – James Waldby - jwpat7 Oct 25 '12 at 22:53
• I didn't mean any technical definition of "geometric arrangement"; I was just referring to the idea that a quincunx describes how five items might be arranged in a geometric pattern, such as dots on the side of a die, whereas a triangle describes a shape. I use these words in their lay meanings—the senses you would find in an ordinary dictionary. – nohat Oct 25 '12 at 23:26