Definition of prismatic

The word "prismatic" comes from the ancient Greek word "prisma," meaning "glass shape with flat surfaces." It was coined by Sir Isaac Newton in the 17th century to describe the phenomenon of separated white light into a spectrum of colors that occurs when light passes through a transparent object with different angles, such as a prism. In this process, known as refraction, light waves bend as they exit a dense medium (such as glass) to a less dense one (such as air), dispersing into a spectrum of colors due to the different wavelengths of light traveling at different speeds. The term "prismatic" is still commonly used today to describe anything that refracts light and separates it into its component colors, such as rainbows, crystal prisms, or the dispersion of light in a bicycle reflector. It is also used in a more generic sense to describe things that appear as if they are made up of nearly parallel faces, such as in geology to describe certain types of columnar rock formations.