Tridecagon (or triskaidecagon).
Check out a list that includes the first 20 at the University of Regina Related Link, below.
Shapes with 12 to 20 sides are named as follows: a 12-sided shape is called a dodecagon, a 13-sided shape is a triskaidecagon, a 14-sided shape is a tetradecagon, a 15-sided shape is a pentadecagon, a 16-sided shape is a hexadecagon, a 17-sided shape is a heptadecagon, an 18-sided shape is an octadecagon, a 19-sided shape is a nonadecagon, and a 20-sided shape is an icosagon.
a 4 sided shape is called a quadrilateral
== == A 56 sided shape is called a Pentacontakaihexagon.
A 600-sided shape is a hexcosiagon.
A twelve sided shape is a dodecagon.
Tridecagon
A 13 sided polygon is called either a triskaidecagon or tridecagon.
Triskaidecahedron
tridecagon (or triskaidecagon)
triskaidecagon or a tridecagon
It can either be called an Triskaidecagon or a Tridecagon.
it is called a seven sided shape in Canada
The 22 sided shape is called a: ICOSIKAIDIGON
A 90 sided shape is called Enneacontagon.
Hommasquabblelagagon
A five-sided shape is called a pentagon.
A seven sided shape is called a heptagon.