A 'color scheme' refers to a coordinated set of colors used in design. Determining the 'best' color scheme is subjective and depends on the context, such as the intended application, the audience, and the aesthetic preferences. For design, color schemes often include a primary color, secondary colors, and an accent color. Popular color schemes include monochromatic, complementary, analogous, and triadic schemes. To choose the best color scheme, consider the principles of color theory, such as harmony and contrast, and test different combinations to see which one works best for your specific purpose.