absorption coefficient

The ratio of the linear rate of change of intensity of roentgen rays in a given homogeneous material to the intensity at a given point within the same mass.

1. The milliliters of a gas at standard temperature and pressure that will saturate 100 milliters of liquid.
2. The amount of light absorbed in 1 atom or in 1 unit of thickness or mass of a given substance.

The noun has one meaning:

Meaning #1: a measure of the rate of decrease in the intensity of electromagnetic radiation (as light) as it passes through a given substance; the fraction of incident radiant energy absorbed per unit mass or thickness of an absorber
  Synonyms: coefficient of absorption, absorptance