The gyroelongated bipyramids are the polyhedra constructed with a bipyramid and an antiprism. Their dual polyhedra are the truncated trapezohedra. The bipyramid is sliced into two congruent pyramids and then attached to the bases of an antiprism in between; such a process of construction is known as gyroelongation. The resulting construction has triangular faces, classified as simplicial polyhedron. There are infinitely many members of gyroelongated bipyramids.