Red

Red is any of a number of similar color evoked by light consisting predominantly of the longest wavelengths of light discernible by the human eye, in the wavelength range of roughly 625–740 nm. Longer wavelengths than this are called infrared, or below red and cannot be seen by the naked human eye. Red is used as one of the additive primary color of light, complementary to cyan, in RGB color systems. Red is also one of the subtractive primary colors of RYB color space but not CMYK color space. In human color psychology, red is associated with heat, energy and blood, and emotions that stir the blood, including anger, passion, and love. The word red comes from the Old English rēad. Further back, the word can be traced to the Proto-Germanic rauthaz and the Proto-Indo European root reudh-. This is the only color word which has been traced to an Indo-European root. In the English language, the word red is associated with the color of blood, certain flowers (i.e. roses), and ripe fruits ... full article at wikipedia