What is the proper name for a cube which is stretched in one direction. So that it is really four rectangles of the same size with two squares at the ends.
Elongated/stretched cube? Rectangular/square prism?
Because all the angles are right angles, it's a cuboid.
Reference: Maths is fun
A prism where two opposite sides are triangles is called a triangular prism. What a prism is called is determined by the faces which are not rectangles.