- A solid figure whose bases or ends have the same size and shape and are parallel to one another, and each of whose sides is a parallelogram.
- A transparent body of this form, often of glass and usually with triangular ends, used for separating white light passed through it into a spectrum or for reflecting beams of light.
- A cut-glass object, such as a pendant of a chandelier.
- A crystal form consisting of three or more similar faces parallel to a single axis.
- A medium that misrepresents whatever is seen through it.
[Late Latin prīsma, from Greek prīsma, thing sawed off, prism, from prīzein, to saw, variant of prīein.]
