An octagon is a polygon with eight sides and eight angles. The word "octagon" comes from the Greek words "okto," meaning eight, and "gonia," meaning angle. Each interior angle in a regular octagon measures 135 degrees, and the sum of all interior angles is 1,080 degrees. Octagons are commonly seen in everyday life, such as in the shape of stop signs, which are designed to be easily recognizable. They can also be found in architecture and design, where their unique shape adds visual interest. Other polygons, like triangles and hexagons, have fewer sides and angles.