Regular Convex Solid (Noun)

Any one of five solids whose faces are congruent regular polygons and whose polyhedral angles are all congruent.

Nouns denoting two and three dimensional shapes.

The term Platonic solid is synonymous with regular convex solid and some mathematicians even use the term polyhedron interchangeably with regular convex solid.
A regular convex solid has identical regular polygon faces with the same number of sides and each vertex is a vertex of the same number of faces.
There are five different types of regular convex solids as they are the only ones with these properties.
He also showed that there are only five possible regular convex solids and therefore there are only five possible types of Polyhedral dice.
He systematically examined them and rigorously justified that there are only five possible regular convex solids that are three-dimensional polyhedra.