Abbreviation for cyan, magenta, yellow and key (black), the four process colors.<br><br>Cyan Magenta Yellow blacK. A system for reproduction color in print ? "four-color printing," a cluster of three colors -- cyan, yellow, and magentacreating the color spectrum using cyan, magenta, yellow, and black.The diagram to the left shows some of the colors possible just with the first three of these colors. With the addition of black, the range increases further.If you&#39;re a Web designer, you&#39;re used to working in RGB. Unfortunately, print graphics use either spot colors, usually CMYK or Pantone Matching System (PMS). You can use PMS colors (or spot colors) if your graphics have three colors or less (in reality, you can use them if there&#39;s more than three colors, but it&#39;s generally more cost effective to go to CMYK if you have more than three colors). Once you have at least four colors, it&#39;s time to go to CMYK. Keep in mind, though, that RGB colors tend to look much brighter and more saturated than either PMS or CMYK colors. To be able to show your client what your graphic will look like when printed, you&#39;ll need to get a Pantone swatch book that shows both RGB and CMYK colors. Pantone&#39;s ColorSuite for Internet will also help you ensure colors between print and Web.Also see color wheel.