attenuation coefficient

Analogous to absorption coefficient but taking into account also the effects due to scattering and luminescence. It was formerly called extinction coefficient.
Source:
Green Book, 2nd ed., p. 32
See also:
Orange Book, p. 212
PAC, 1996, 68, 957 (Glossary of terms in quantities and units in Clinical Chemistry (IUPAC-IFCC Recommendations 1996)) on page 963