A polyhedron with 8 faces. The regular octahedron (seeregular polyhedron) is one of the Platonic solids and its faces are equilateral triangles. It has 6 vertices and 12 edges.
Geology and Earth Sciences
A three-dimensional, eight-sided form in which all the faces are equilateral triangles (i.e. it resembles a double pyramid). In crystallography, a crystal form in which the crystal faces cut all three crystallographic axes at equal distances.