In geometry, a trigonal trapezohedron or trigonal deltohedron is a three-dimensional figure formed by six congruentrhombi. They are a special kind of parallelepiped, and are the only parallelepipeds with six congruent faces. Since all of the edges must have the same length, every trigonal trapezohedron is also a rhombohedron.
The trigonal trapezohedron is the simplest of the trapezohedra, an infinite sequence of polyhedra which are dual to the antiprisms. The dual of a trigonal trapezohedron is a uniform triangular antiprism, i.e. a regular octahedron.
A trigonal trapohederon with square faces is a cube.