It is called a dinopagon.
The name of a 12 sided polygon is Dodecagon.
A 8 sided polygon is called a octagon.
The name of a 9 sided polygon is Nonagon.
The name of a 19 sided polygon is enneadecagon.
The name of a 17 sided polygon is Heptadecagon.
chilioogon
A thirty-one sided polygon would be called a triacontakaihenagon.
The name of a 12 sided polygon is Dodecagon.
name of 4000 sided polygon
A 8 sided polygon is called a octagon.
The name of a 10 sided polygon is Decagon.
The name of a 19 sided polygon is enneadecagon.
The name of a 9 sided polygon is Nonagon.
The name of a 15 sided polygon is Pentadecagon.
The name of a 7 sided polygon is Heptagon.
The name of a 17 sided polygon is Heptadecagon.
The name of a 8 sided polygon is Octagon.