Red is any of a number of similar colors evoked by light consisting predominantly of the longest wavelengths of light discernible by the human eye, in the wavelength range of roughly 630–740 nm. Longer wavelengths than this are called infrared (below red), and cannot be seen by the naked human eye. Red is used as one of the additive primary colors 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 bravery, purity, happiness, good luck, heat/fire, energy, and blood, and emotions that "stir the blood", including anger, passion, love, pain, and sacrifice.

red - characterized by violence or bloodshed; "writes of crimson deeds and barbaric days"- Andrea Parke; "fann'd by Conquest's crimson wing"- Thomas Gray; "convulsed with red rage"- Hudson Strode