Polygonia is a term used in geometry to refer to a closed shape with straight sides, specifically with at least three sides. However, there are several synonyms for polygonia, including polygon, polyhedron, and polytope. These terms can be used interchangeably depending on the context. A polygon is a simple two-dimensional shape, while a polyhedron is a three-dimensional shape with flat surfaces or faces. A polytope is a general term for any n-dimensional shape or object, where n is a positive integer. These synonyms for polygonia can be useful in mathematics, engineering, and design, and can help describe and analyze complex shapes and structures.