The shape with eight sides is called an octagon. Octagons are polygonal shapes characterized by having eight straight edges and eight vertices. In geometry, they can be regular (with all sides and angles equal) or irregular (with unequal sides and angles). The most recognized example of an octagon is the stop sign used in traffic signals, which is a regular octagon with equal sides and angles. Octagons are commonly studied in mathematics and can be found in various real-world applications, including architecture, design, and art.