The terms “white noise” and “pink noise” refer to specific types of noise that are used for testing electronic equipment, and for other purposes as well. The color names stem from a comparison to white light, which contains all wavelengths of visible light from red (longest wavelength, lowest frequency) to violet (shortest wavelength, highest frequency). When all of the light wavelengths are in balance we see white light. If the redder wavelengths are in greater proportion to the others, the light shifts to the pink or red. As we will see below, this same idea applies to noise sources.
Via Hugo V. Monteiro