The Math League
The Math League: Figures and Polygons
This website has basic definitions for most polygons, regular and irregular.
Math Is Fun
Math Is Fun: Regular 2 D Shapes
This tutorial provides illustrations for regular 2-D shapes as well as a definition for polygons and for regular polygons.
Science Struck
Science Struck: List of Different Types of Geometric Shapes
A comprehensive list of 2D shapes and 3D solids with everything from a triangle to a dodecahedron. Includes illustrations and short descriptions of attributes for each.
National Council of Teachers of Mathematics
The Math Forum: Defining Geometric Figures
This site provides an in-depth definition of a two-dimensional figure and a three-dimensional figure. Related terms include arcs, vertices, polygon, and many more.
Quia
Ixl Learning: Area of Rhombuses
Brush up on your math skills relating to the area of rhombuses then try some practice problems to test your understanding.
Quia
Ixl Learning: Area of Triangles
Brush up on your math skills relating to the area of triangles then try some practice problems to test your understanding.
Other
Stat Soft: Statistics Glossary
Dozens of statistical terms are defined and illustrated in this glossary.
Other
University of Edinburgh: Glossary of Introductory Computer Graphics Terms
This website, from the University of Edinburgh, provides a lengthy glossary of computer graphics terms written by Olin Lathrop, author of "The Way Computer Graphics Work". This site provides simple definitions of basic terms; no graphics...