convex

no line that contains a side of the polygon contains a point in the interior of the polygon

concave

A polygon that is not convex.

regular

A polygon that is both equilateral and equiangular.

triangle

a three-sided polygon

quadrilateral

a four-sided polygon

pentagon

a five-sided polygon

hexagon

a six-sided polygon

heptagon

a seven-sided polygon

nonagon

a nine-sided polygon

octagon

an eight-sided polygon

dodecagon

a twelve-sided polygon

decagon

10 sided polygon

n-gon

a polygon with n sides

polygon

a closed plane figure bounded by straight sides

equilateral

all sides are congruent