noun Physics.
- the capacity of a substance to absorb radiation, expressed as the common logarithm of the reciprocal of the transmittance of the substance.
noun
- physics a measure of the light-absorbing ability of an object, expressed as the logarithm to base 10 of the reciprocal of the internal transmittanceSee transmittance
n.
- In spectrophotometry, equal to 2 minus the log of the percentage transmittance of light.extinction optical density