Deborah,

A recatanglar prism has parallel bases that are congruent rectangles and the remaining faces are parallelograms. A cardboard carton has the shape of a rectangular prism and so does a child's block. (In this case the bases are squares, but squares are also rectangles.) The sides do not need to be perpendicular to the base so the shape outlined in orange below is a rectangilar prism.

Image from the Container Store

Harley