gradient

(grāˈdē-ənt)

1. A rate of inclination; a slope.
2. An ascending or descending part; an incline.
3. Physics The rate at which a physical quantity, such as temperature or pressure, increases or decreases relative to change in a given variable, especially distance.
4. Mathematics A vector having coordinate components that are the partial derivatives of a function with respect to its variables.
5. Biology A series of progressively increasing or decreasing differences in the growth rate, metabolism, or physiological activity of a cell, organ, or organism.