9 color schemes

Quick answer：

A 'color scheme' refers to a set of colors used in design to create a cohesive and visually appealing look. There are various types of color schemes, such as monochromatic, complementary, analogous, triadic, and tetradic. A '9-color scheme' could be a more complex or varied selection of colors, possibly used in graphic design or interior design to create a rich and diverse visual experience.