A color wheel is a circular diagram that represents the relationships between different colors. It typically includes primary colors, such as red, blue, and yellow, which cannot be created by mixing other colors. Secondary colors, like green, orange, and purple, are formed by mixing two primary colors. The color wheel also features tertiary colors, which are created by mixing a primary color with a secondary color. This tool is widely used in art and design to help people understand color harmony and create visually appealing combinations. It serves as a guide for artists, designers, and anyone interested in color theory.