Blue | Description, Etymology, & Facts | Britannica

blue, in physics, light in the wavelength range of 450–495 nanometres in the visible spectrum. After violet, blue is the spectral region with the shortest wavelengths discernible to the human eye. In art, blue is a colour on the conventional wheel, located between green and violet and opposite orange, its complement. Blue is a basic colour term added to languages after black, white, red …

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