Color channel
From The Glossary of Digital Photography
The color portion of an image consisting of a single color. An RGB image is made of three colors: red, green, and blue. Each of those colors is a single channel of tonal and color information, shown in Photoshop as a single black-and-white image when the color image is split into the three channels. When those black-and-white images are combined with a color filter for each, the complete color image is displayed. See also RGB
