In geometry, a prism is a polyhedron made of two parallel copies of some polygonal base joined by faces that are rectangles or parallelograms.
In the case of these joining faces being rectangular, the object is said to be a right prism.
A prism with at least one rectangular face has all faces rectangular, and is called a rectangular prism; a rectangular prism with a square face has two opposite square faces, and is called a square prism. A prism that is both right and rectangular is a right rectangular prism, also called a cuboid.
Regular prisms have all equal edge lengths, and faces made of regular polygons.
Right prisms with regular bases form one of the two infinite series of vertex-uniform polyhedra, the other series being the antiprisms. The cube is a particular type of right square prism which is also edge- and face-uniform and so counts among the Platonic solids.
The dual of a prism is a bipyramid. The volume of a prism is the product of the area of one of the bases and the distance between them.
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