An Octagon is a polygon with 8 sides and 8 vertices (corners).
A regular octagon has all eight sides the same length and each side is 135° and all the angles added together equals 1080°.
An eight-sided star, commonly called a octagram has one regular octagon inside it.
The octagonal prism has 2 octagons in it: one on the top, and the other on the bottom.
A brown octagon on a white background.