octahedron
A hexahedron is a solid with six plane faces, and a cuboid is a six-sided figure each face of which is a rectangle.
'Enneahedron' - a solid figure with nine faces
A pentagonal heptahedron. A heptahedron is a solid figure with seven faces, and a pentagon is a five-sided plane figure.
I believe it to be a dodecahedron I believe it to be a dodecahedron +++ You believe correctly: it is a dodecahedron.
octahedron
A hexahedron is a solid with six plane faces, and a cuboid is a six-sided figure each face of which is a rectangle.
If you ask this, you fail Octahedron
It is a regular quadrilateral which is a square
A polyhedron is a solid figure with many plane faces, typically more than six.
'Enneahedron' - a solid figure with nine faces
A solid figure with twenty faces is called an Icosahedron.
A solid has a depth, a plane figure does not.
A pentagonal heptahedron. A heptahedron is a solid figure with seven faces, and a pentagon is a five-sided plane figure.
were two or more faces of a solid figure
I believe it to be a dodecahedron I believe it to be a dodecahedron +++ You believe correctly: it is a dodecahedron.
A pyramid, as well as any other solid figure bounded by plane polygons or faces, is a polyhedron.