diffusion coefficient, D

https://dx.doi.org/10.1351/goldbook.D01719
Proportionality constant D, relating the flux of amount of entities B to their concentration gradientJ n = − D ∇ c B.
Source:
See also:
PAC, 1996, 68, 957 (Glossary of terms in quantities and units in Clinical Chemistry (IUPAC-IFCC Recommendations 1996)) on page 969