An array of very narrow parallel slits or apertures which, when white light is projected through the openings, breaks it down into the colors of the spectrum, due to the diffraction of light waves as they pass through the openings. A diffraction grating produces a spectral effect of such a large magnitude due to the reinforcement of the light waves from adjacent slits. A spectrum produced using a diffraction grating contains all the colors in an order that is the reverse of that obtain using a prism. And, unlike a prism, a diffraction grating doesn't distort the red end of the spectrum. A prism also isn't based on the process of draffraction; see Dispersion.
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