Octo=eight, Octagon
An irregular polygon
no
It all depends on what kind of polygon it is. It may have no congruent sides or all congruent sides.
A decagon is a polygon that has 10 sides
It is a decagon that has 10 sides
hectagon
hendecagon
A pentagon
a heptagon
A 7 sided polygon is an heptagon
14-gon