A color wheel or color circle is an organization of color hues around a circle, showing relationships between colors considered to be primary colors, secondary colors, complementary colors, etc.
Artists typically use red, yellow, and blue primaries (RYB color model), so these are arranged at three equally-spaced points around their color wheel. Printers and others who use modern subtractive color methods and terminology use magenta, yellow, and cyan as subtractive primaries.
Color scientists and psychologists often use additive primaries, such as red, green, and blue, and often refer to their arrangement around a circle as a color circle, as opposed to a color wheel.
The arrangement of colors around the color circle is often considered to be in correspondence with the wavelengths of light, as opposed to hues, in accord with the original color circle of Isaac Newton. Modern color circles include the purples, however, between red and violet.
Intermediate and interior points of color wheels and circles represent color mixtures. In a paint or subtractive color wheel, the center is usually (but not always) black, representing all colors of light being absorbed; in a color circle, on the other hand, the center is white or gray, indicating a mixture of different wavelengths of light (all wavelengths, or two complementary colors, for example).
Some sources use the terms color wheel and color circle interchangeably, though the one term or the other may be more prevalent in certain fields or certain versions as mentioned above. Some reserve the term color wheel for mechanical rotating devices, such as color tops or filter wheels. Others classify various color wheels as color disc, color chart, and color scale varieties