A hexadecagon is a polygon with sixteen sides and sixteen angles. The term comes from the Greek word "hexadeca," meaning sixteen, and "gon," meaning angle. Each internal angle of a regular hexadecagon measures 157.5 degrees, and the sum of all internal angles is 2,520 degrees. Hexadecagons can be found in various fields, including mathematics and architecture. They can be regular, where all sides and angles are equal, or irregular, with varying side lengths and angles. The study of hexadecagons is part of the broader topic of geometry, which explores shapes, sizes, and properties of space.