absorptivity

plural absorptivities

1. The quality of being absorptive; absorptiveness.First known use First attested in the mid 19ᵗʰ century.
2. natural sciencesThe fraction of radiation absorbed by a surface to the total radiation incident on the surface.First known use First attested in the mid 19ᵗʰ century.
3. analytical chemistryThe constant a in the Beer's law relation A = abc, where A is the absorbance, b the path length, and c the concentration of solution. Also known as absorptive power. Formerly known as absorbency index; absorption constant; extinction coefficient.