prism (prĭzˈəm)

1. 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.
2. 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.
3. Such a body used in testing or correcting imbalance of the extrinsic ocular muscles.

Related Forms:

• pris·matˈic (-mătˈĭk) adjective