Platonic solids are three-dimensional shapes with identical faces, edges, and angles. There are five types: tetrahedron, cube, octahedron, dodecahedron, and icosahedron. Each solid is defined by its regular polygonal faces, meaning all sides and angles are equal. These shapes are named after the ancient Greek philosopher Plato, who associated them with the classical elements: earth, air, fire, water, and the cosmos. Platonic solids are significant in various fields, including mathematics, art, and architecture, due to their symmetrical properties and aesthetic appeal.