Octagons are polygons with eight sides. The root word oct- indicates the number eight, as in octopus (which has eight legs). The stop sign form of the octagon has its sides parallel to the x- and y-axes; octagons can also be oriented with its vertices along these axes.
An octagon is a two-dimensional polygon. For three-dimensional shapes (polyhedras), a shape with eight faces is called an octahedron. This include shapes such as a hexagonal prism.Learn more about Shapes