absorption coefficient

in biology
https://doi.org/10.1351/goldbook.AT06797
Ratio of the absorbed quantity (uptake) of a substance to the administered quantity (intake).
Source:
PAC, 2004, 76, 1033. 'Glossary of terms used in toxicokinetics (IUPAC Recommendations 2003)' on page 1036 (https://doi.org/10.1351/pac200476051033)