enneahedron; nonahedron
A polyhedron with nine faces. Technical term used in geometry.
An enneahedron is a polyhedron with nine faces.
Compound of 九 (きゅう, 'nine') + 面 (めん, 'face') + 体 (たい, 'body'), following the pattern of other geometric terms such as 四面体 (tetrahedron) and 六面体 (hexahedron).