A prism is a three-dimensional object created by connecting a polygon with a translated version of the same polygon, vertex to vertex. The two parallel congruent polygons are called bases. The other faces are called lateral faces. The intersection of two lateral faces is called a lateral edge. A prism with perpendicular lateral faces and bases is a right prism. Otherwise, it is is called an oblique prism. The lateral faces of a prism can either be rectangles or parallelograms. In an oblique prism, at least one lateral face must be a parallelogram. In contrast, in a right prism, all lateral faces are rectangles.

Prisms can be categorized by the shape of their bases. For example, a prism with a triangular base is called a triangular prism. A rectangular prism, on the other hand, has a rectangular base.

The surface area of a prism is the sum of its lateral area and the area of the two bases.