What distinguishes a heptagon from other polygons?

A heptagon is specifically defined by having 7 sides. This unique property sets it apart from other polygons, as the number of sides is a fundamental aspect of their classification. In contrast, other choices refer to polygons with fewer or more sides: a polygon with 5 sides is a pentagon, one with 6 sides is a hexagon, and one with 8 sides is an octagon. Thus, the defining characteristic that makes a heptagon distinct is its seven-sided structure, which is a critical feature in geometry for distinguishing between different types of polygons.