Names for Polygons, Groups, Number Systems, Tuples, and Greek and Latin Prefixes

 

Number
System		 Prefixes
Num Polygon Group Tuple Greek Latin
1 monogon1 unit unary single mono–
haplo–		 uni–
2 digon pair
duo
couple		 binary double di– duo–
bi–
3 triangle trio ternary triple tri– tre–
ter–
4 quadrilateral quaternary quadruple tetra– quadri–
quadr–
5 pentagon quinary quintuple penta–
pent–		 quinque–
quinqu–
quint–
6 hexagon sextet senary sextuple hexa–
hex–		 sexa–
sex–
7 heptagon septenary septuple hepta–
hept–		 septua–
8 octagon octet octal octuple octa–
oct–		 octo–
oct–
9 enneagon
nonagon		 ennead nonary nonuple ennea– nona–
10 decagon decade decimal decuple deca–
deka–		 deci–
Number
System		 Prefixes
Num Polygon Group Tuple Greek Latin
11 hendecagon
undecagon
endecagon		 undecimal2 undecuple hendeca–
hendeka–		 undeca–
12 dodecagon dozen duodecimal duodecuple dodeca– duodeca–
13 tridecagon
triskaidecagon		 baker’s dozen tredecimal tredecuple
14 tetradecagon
tetrakaidecagon		 tetradecimal quattuor-decuple G: tetrakaideca–
L: quattuordec–
15 pentadecagon
pentakaidecagon		 pentadecimal quindecuple
16 hexadecagon
hexakaidecagon		 hexadecimal sexdecuple
17 heptadecagon
heptakaidecagon		 septendecimal septendecuple
18 octadecagon
octakaidecagon		 octodecimal octodecuple
19 enneadecagon
enneakaidecagon		 nonadecimal
enneadecimal3		 novemdecuple
20 icosagon score vigesimal viguple
Number
System		 Prefixes
Num Polygon Group Tuple Greek Latin
21 unvigesimal
22 duovigesimal
23 trivigesimal
24 icositetragon
icosikaitetragon		 tetravigesimal
25 pentavigesimal
26 hexavigesimal
27 hepta-vigesimal
28 octovigesimal
29 ennea-vigesimal
30 triacontagon trigesimal
32 duotrigesimal
33 tritrigesimal
34 tetratrigesimal
35 penta-trigesimal
36 hexatrigesimal
38 octotrigesimal
40 quadragesimal
144 144-gon gross centetetra-quadragesimal
360 trecento-sexagesimal
1728 1728-gon great gross
∞ apeirogon4 N/A
Number
System		 Prefixes
Num Polygon Group Tuple Greek Latin

Constructing Names of Polygons with 20 to 100 Edges

To construct the name of a polygon with more than 20 and less than 100 edges, combine the prefixes as follows. The “kai” term applies to 13-gons and higher.5

Tens and Ones Final Suffix
–kai– 1 –hena– –gon
20 icosi– (icosa– when alone) 2 –di–
30 triaconta– (or triconta–) 3 –tri–
40 tetraconta– (or tessaraconta–) 4 –tetra–
50 pentaconta– (or penteconta–) 5 –penta–
60 hexaconta– (or hexeconta–) 6 –hexa–
70 heptaconta– (or hebdomeconta–) 7 –hepta–
80 octaconta– (or ogdoëconta–) 8 –octa–
90 enneaconta– (or eneneconta–) 9 –ennea–

See Also

Otto, Keegan. “Keegan Otto’s answer to What is the name of a polygon that has 21-30 sides?“. Quora. January 30, 2018.

Wikipedia contributors. “List of numeral systems”. Wikipedia. Accessed August 14, 2019.

Wikipedia contributors. “List of polygons”. Wikipedia. Accessed August 13, 2019.

Footnotes

  1. In Euclidean geometry a monogon is a degenerate polygon because its endpoints must coincide, unlike any Euclidean line segment. Most definitions of a polygon in Euclidean geometry do not admit the monogon.
    Wikipedia contributors. “Monogon”. Wikipedia. Accessed August 12, 2019.
  2. Wikipedia contributors. “List of numeral systems”. Wikipedia. Accessed August 14, 2019.
  3. Wikipedia contributors. “List of numeral systems”. Wikipedia. Accessed August 14, 2019.
  4. A degenerate polygon of infinitely many sides.
    Wikipedia contributors. “Polygon”. Wikipedia. Accessed August 12, 2019.
  5. Wikipedia contributors. “Polygon”. Wikipedia. Accessed August 12, 2019.

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