cubes and cuboids
Hexahedron
A rectangular prism.
It is called a hexagon because it has six faces and also six vertexes.
A hexahedron is a solid with six plane faces, and a cuboid is a six-sided figure each face of which is a rectangle.
a cube
There is no such polyhedron.
It is a cube
The general term is a hexahedron. If the six faces are all equal squares, then you can also call it a cube.
rectangular prism
A hexahedron has six faces. Regular hexahedrons include the rectangular prism, the cuboid, and the cube.
There is no solid figure with only four edges. The smallest solid figure is the tetrahedron, made up of four triangular faces, but it has six edges.
'Enneahedron' - a solid figure with nine faces