Definition of prism
1
: a polyhedron with two polygonal faces lying in parallel planes and with the other faces parallelograms
2 a
: a transparent body that is bounded in part by two nonparallel plane faces and is used to refract or disperse a beam of light
b
: a prism-shaped decorative glass luster
3
: a crystal form whose faces are parallel to one axis;
especially
: one whose faces are parallel to the vertical axis
4
: a medium that distorts, slants, or colors whatever is viewed through it
