prism
A prism is a three-dimensional shape. Both ends of a prism are congruent. Its cross-section is also congruent all the way along its length.
The shape at both ends gives the prism its name. For example, if the shape at both ends is a triangle, it is a triangular prism – think of the packaging on a Toblerone chocolate bar. A tin of baked beans is an example of a circular prism (cylinder) and a book is an example of a rectangular prism (cuboid).
The formula for the volume of a prism is: