What shape is defined as having 9 sides?

A shape with 9 sides is known as a nonagon. The term "nonagon" is derived from Latin, where "nona" means nine and "gon" signifies sides. Understanding polygons requires familiarity with their prefixes, as many shapes are categorized based on the number of sides they possess.

In contrast, an octagon features 8 sides, making it a different polygon entirely. A decagon is a ten-sided figure, while a dodecagon has 12 sides. Knowing these definitions helps in visualizing and distinguishing various polygons based on their number of sides, reinforcing the concept that each shape's name is indicative of its geometry. This knowledge is crucial when teaching students about various polygons and other geometric concepts in mathematics.