From: Manuel

Elementary level (6th Grade)
Student Question

What do you call a 13 sided polygon?
Is there a list of the different names?

Thank you for your help.

Hi Manuel

There seems to be an "official"set of names for polygons, uniformly derived from the Greek (after 4 sides).

Number of sides	Name
3	triangle or trigon
4	quadrilateral or tetragon
5	pentagon
6	hexagon
7	heptagon
8	octagon
9	enneagon
10	decagon
11	hendecagon
12	dodecagon
13	triskaidecagon or tridecagon
14	tetrakaidecagon or tetradecagon
15	pendedecagon
16	hexdecagon
17	heptdecagon
18	octdecagon
19	enneadecagon
20	icosagon

After about 6 sides mathematicians usually refer to these polygons as n-gons. So your 13 sided polygon I would call a 13-gon.

Cheers,
Walter and Harley