Cyan from Greek, transliterated: kýanos, meaning "dark blue substance" may be used as the name of any color in the range between blue and green. Historically, it was not distinguished as a separate part of the visible spectrum or the color wheel -- colors which are now recognized as cyan were traditionally included in "blue," partly "green," or were considered mixed (intermediate) colors without a specific color term. In additive color system, cyan is used to refer to the color obtained by mixing equal amounts of green and blue light. It also can be made by the removal of red from white light, which makes it the complement of red: cyan pigments absorb red light.

The first recorded use of cyan blue (as noted above, "cyan blue" was the name used for the color "cyan" in the 19th century) as a color name in English was in 1879. Cyan colored tiles are often used to pave swimming pools to make the water within them seem more intensely colored, and therefore more inviting.

Some tones of color close to cyan in the cyan color range are teal, turquoise, electric blue and aquamarine.