1. the milliliters of a gas at standard temperature and pressure that will saturate 100 ml of liquid;
2. the amount of light absorbed in passing through 1 cm of a 1 molar solution of a given substance, expressed as a constant in Beer-Lambert law; Cf. specific absorption coefficient.
3. in x-ray, a measure of the rate of decrease of intensity of a beam in its passage through a substance, resulting from a combination of scattering and conversion to other forms of energy.