[prism] n [LL prismat-, prisma, fr. Gk, lit., anything sawn, fr. priein to saw] (1570) 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; esp: one whose faces are parallel to the vertical axis
4: a medium that distorts, slants, or colors whatever is viewed through it