In optics, violet is the shortest-wavelength color of visible light, appearing at the end of the spectrum opposite to red.
Violet light generally occupies wavelengths of roughly 380 to 435 nanometers. Because shorter wavelengths correspond to higher frequencies, violet also has the highest frequency—and therefore the highest photon energy—of the visible colors.
The visible spectrum is commonly remembered as red, orange, yellow, green, blue, indigo, and violet. Ultraviolet lies beyond violet at even shorter wavelengths, but it is invisible to typical human vision. Indigo is often listed between blue and violet, although its status as a separate spectral color is debated.
Violet should not be confused with purple. Violet is a spectral color produced by a narrow range of wavelengths, while purple usually results from combining red and blue light. Isaac Newton included violet among the seven colors he identified in the visible spectrum in the 17th century.