An octagon is a polygon that has 8 sides
An angle cannot have 8 sides. If you're thinking of a shape with 8 sides, that's an octagon.
OCTOgon
There is no collective name for the infinite family of polygons with more than 8 sides.
Ummm... A triangle has 3 sides.
octagon
octagon
Octagon
Octagon
Octagon
octagon-8 sides
I'm assuming you mean a shape with 8 sides or angles. If so, you are speaking about an octogon.