It is something that is not a polyhedron. that would include
Examples of non polyhedron are cone cylinder spere
A non polyhedron with 0 bases is a sphere.
A polyhedron is a three-dimensional solid with flat faces, straight edges, and sharp corners, while a non-polyhedron does not have these characteristics. Polyhedra are made up of polygons that enclose a single region of space, while non-polyhedra may have curved faces or intersecting edges. In mathematical terms, a polyhedron satisfies Euler's formula (V - E + F = 2), where V is the number of vertices, E is the number of edges, and F is the number of faces, while a non-polyhedron does not.
A non polyhedron does not have these properties, maybe it is not closed, maybe one or more of the sides is a curved surface. In some branches of topology the sides of a polyhedron cannot intersect each other.http://wiki.answers.com/What_is_the_difference_between_a_polyhedron_and_a_non_polyhedron#ixzz185DDOyd9
Assuming that you mean diagonal (not diagnol) lines, they are straight lines that join non-adjacent vertices in a polygon or polyhedron.
A polyhedron is a three-dimensional geometric shape with flat polygonal faces, straight edges, and vertices, such as cubes and pyramids. In contrast, a non-polyhedron includes shapes that do not fit this definition, such as spheres, cylinders, and cones, which have curved surfaces and do not consist entirely of flat faces. Essentially, the key difference lies in the presence of flat polygonal faces in polyhedra versus the curved surfaces in non-polyhedra.
A polyhedron has "many sides" (by definiton). The only 3-D shape which does not have "many sides" is a sphere (which technically only have one "side").
A cylinder is one example.
If you mean a decahedron then it is a polyhedron with 10 faces
A shape with a lot of sides and angles.
If, by "sides" you mean faces, then the answer is a pentahedron.
No, they are the faces of the polyhedron.