In cathode-ray tube (CRT) terms, a triad is a group of 3 phosphor dots coloured red, green, and blue on the inside of the CRT display of a computer monitor or television set.^[1] By directing differing intensities of cathode rays onto the 3 phosphor dots, the triad will display a colour by combining the red, green and blue elements. However, triads are not pixels, and multiple triads will form one logical pixel of the displayed image.

In liquid-crystal displays (LCDs), colours are similarly composed of these 3 fundamental colours.