Definition of prisms:
(n) :
(optics) A transparent block in the shape of a prism (sense 1), typically with triangular ends, used to reflect or refract light.
(n) :
(geometry) A polyhedron with parallel ends of the same polygonal shape and size, the other faces being parallelogram-shaped sides.
(n) :
An object having the shape of a geometrical prism (sense 1).
(n) :
(crystallography) A crystal in which the faces are parallel to the vertical axis.
(n) :
(by extension, surveying) A retroreflector (“device which reflects light back to its source with minimal scattering”) which is usually attached to a surveying pole as a target for a total station which emits a light beam at the device and calculates how long it takes to be reflected back in order to measure distance.
(n) :
(figurative) A perspective that colours one's perception.