Prism (noun)

1. A piece of glass or other transparent material with flat, polished surfaces that refract light, used to produce spectra or to direct light beams.
2. A crystal or other object having a triangular cross-section that is used to separate light into its component colors.
3. A triangular piece of glass or other transparent material that can be used to reflect or refract light.

Origin:

The word prism comes from the greek word prisma, meaning "something sawed" and it has been in use since the 16th century.

Examples:

1. The prism refracted the light into a spectrum.
2. A prism is used to create a rainbow effect.
3. The prism was used to split the light into different colors.
4. The prism was placed on the lens to correct the chromatic aberration.
5. The camera was fitted with a prism to change the angle of view.