A color belonging to any of three groups each of which is regarded as generating all colors, with the groups being:
Additive, physiological, or light primaries red, green, and blue. Lights of red, green, and blue wavelengths may be mixed to produce all colors.
Subtractive or colorant primaries magenta, yellow, and cyan. Substances that reflect light of one of these wavelengths and absorb other wavelengths may be mixed to produce all colors.
Psychological primaries red, yellow, green, and blue, plus the achromatic pair black and white. All colors may be subjectively conceived as mixtures of these.