A chromaticity diagram is also known as a "color space diagram" or a "CIE (Commission International de l'Eclairage) diagram." It is a graphical representation of all visible colors based on their chromaticity coordinates. The diagram is often used in color science, lighting design, and colorimetry. Another synonym for the chromaticity diagram is the "color gamut chart." This chart shows the range of colors that can be displayed by a device such as a computer monitor, printer, or TV. Additionally, the diagram is called the "CIE xy diagram" or just the "xy diagram." Regardless of the name, the chromaticity diagram is a vital tool that helps understand the science of colors and light.