Definition, synonyms and related words
Initialism of red, green, blue. (the colors output by a typical cathode-ray tube (i.e. an old computer monitor) used in varying combinations to render all colors)
"The old CRT monitor displayed the image using the rgb color model to create millions of different shades from its three primary light sources."
In plain English: RGB is a color system that mixes red, green, and blue light to create all the colors you see on screens.
"The designer adjusted the rgb values to make sure every color on her website looked perfect under different lighting conditions."