Chromaticity Diagram
From ColorWiki
The Chromaticity Diagram is a horseshoe-shaped graph of the Yxy color space where the Y component has been removed and the x and y components are then graphed in 2 dimensions.
It is a very useful diagram for getting a quick feeling for not only the range of colors humans can perceive but the ranges of colors (gamuts) that different devices can (or cannot) display.
See Also
