Number System 
Prefixes  

Num  Polygon  Group  Tuple  Greek  Latin  
1  monogon^{1}  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 
undecimal^{2}  undecuple  hendeca– hendeka– 
undeca–  
12  dodecagon  dozen  duodecimal  duodecuple  dodeca–  duodeca– 
13  tridecagon triskaidecagon 
baker’s dozen  tredecimal  tredecuple  
14  tetradecagon tetrakaidecagon 
tetradecimal  quattuordecuple  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 enneadecimal^{3} 
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  heptavigesimal  
28  octovigesimal  
29  enneavigesimal  
30  triacontagon  trigesimal  
32  duotrigesimal  
33  tritrigesimal  
34  tetratrigesimal  
35  pentatrigesimal  
36  hexatrigesimal  
38  octotrigesimal  
40  quadragesimal  
144  144gon  gross  centetetraquadragesimal  
360  trecentosexagesimal  
1728  1728gon  great gross  
∞  apeirogon^{4}  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 13gons 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 2130 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
 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.  Wikipedia contributors. “List of numeral systems”. Wikipedia. Accessed August 14, 2019.
 Wikipedia contributors. “List of numeral systems”. Wikipedia. Accessed August 14, 2019.
 A degenerate polygon of infinitely many sides.
Wikipedia contributors. “Polygon”. Wikipedia. Accessed August 12, 2019.  Wikipedia contributors. “Polygon”. Wikipedia. Accessed August 12, 2019.