prism easy definition
A solid with two congruent parallel faces, where any cross section parallel to those faces is congruent to them. Try this Adjust the height of the prism below. Select examples of various types of prism. A prism is a solid that has two faces that are parallel and congruent. These are called the bases of the prism. If you take any cross section of a prism parallel to those bases by making a cut through it parallel to the bases, the cross section will look just like the bases. In the figure above, click 'show cross-section' and drag the cross section up and down.