absorption spectrum Spectrum consisting of dark lines or bands on a colored background, formed when a substance is placed between white light source and spectroscope. The dark lines or bands are due to the absorption of incident radiation by the substance at certain wave lengths. The position of the dark lines formed are unique to each element. Therefore from the positions of these lines, the elements can be identified.

Fraunhofer discovered the absorption lines in spectrum of sunlight. They are called Fraunhofer lines.