"Red" is a color that is at the long wavelength end of the visible spectrum of light, next to orange and opposite violet. It has a dominant wavelength of approximately 625–740 nanometers and is a primary color in the RGB color model and a secondary color (made from magenta and yellow) in the CMYK color model, and is the complementary color of cyan. Red pigment made from ochre was one of the first colors used in prehistoric art. The Ancient Egyptians and Mayans colored their faces red in ceremonies; Roman generals had their bodies colored red to celebrate victories. It was also an important color in China, where it was used to color early pottery and later the gates and walls of palaces.

In addition to its use as a color, "red" can also be used as an adjective to describe something that is of a color at the end of the color spectrum (next to orange) . It can also be used to describe something that is reddish or tinged with red, such as a persons face that is redder than its normal color due to embarrassment, anger, or being out of breath.