This site gives the general definition of a octagon with examples of regular convex and irregular concave octagons. The site has links to related terms, everyday examples, challenging problems, more information, and the interactive check...

A complex look at the octagon, which is an eight-sided polygon, from Mathworld.com.

This picture shows a simple outline of an octagon, a shape featuring eight sides.

This site provides definitions of different types of polygons and figures.

On this site students are instructed to locate different types of polygons on triangle grid paper. This page can be printed so that students can actually draw them. It also gives a definitions link for each polygon.