What is "dual polyhedron"

n. (context mathematics English) Either of a pair of polyhedra in which the faces of one are equivalent to the vertex of the other

In geometry, polyhedra are associated into pairs called duals, where the vertices of one correspond to the faces of the other. Starting with any given polyhedron, the dual of its dual is the original polyhedron. The dual of an isogonal polyhedron, having equivalent vertices, is one which is isohedral, having equivalent faces; the dual of an isotoxal polyhedron (having equivalent edges) is also isotoxal. The regular polyhedra — the Platonic solids and Kepler-Poinsot polyhedra — form dual pairs, with the exception of the regular tetrahedron which is self-dual.

Duality is closely related to reciprocity or polarity.