

Stands for "Red Green Blue." It refers to the three hues of light (red, green, and blue, for those of you that are a little slow), that can mix together to form any color. When the highest intensity of each color is mixed together, white light is created.

For cs2d :
You can also use color-codes at the beginning of your text (©RRRGGGBBB)!
RRR = Red
GGG = Green
BBB = Blue
For example:
©255128000 = Orange
255 = Red
128 = Green
000 = Blue
©255000000 = Red
©000255000 = Green
©000000255 = Blue
©255255000 = Yellow
©255255255 = White
©000000000 = Black
©000255255 = Grey
Source :
www.iwebtool.com
www.cs2d.com