## Wikipedia - Gradiente di concentrazione (it) concentration gradient, $$\text{grad}\: C$$

https://doi.org/10.1351/goldbook.C01227
Differential change in concentration of a component in a given direction in a small distance divided by the distance in that direction.
Notes:
1. It is a vector quantity.
2. May be expressed as amount-of-substance, mass, number, volume, concentration @G02669@.
Source:
PAC, 1996, 68, 957. (Glossary of terms in quantities and units in Clinical Chemistry (IUPAC-IFCC Recommendations 1996)) on page 967 [Terms] [Paper]