The correct term for a shape with eight sides is "octagon." An octagon is a polygon that has eight straight edges and eight vertices. The most familiar example of an octagon is the stop sign used in road traffic, which is commonly red with a white border and the word "STOP" inscribed in the center. Octagons can be regular, meaning all sides and angles are equal, or irregular, where side lengths and angles may vary. The study of octagons, like other geometric shapes, is vital in fields such as architecture, engineering, and design.