GRADIENT

noun Etymology: Latin ~-, gradiens, present participle of gradi Date: 1835 1. the rate of regular or graded ascent or descent ; inclination , a part sloping upward or downward, change in the value of a quantity (as temperature, pressure, or concentration) with change in a given variable and especially per unit distance in a specified direction, the vector sum of the partial derivatives with respect to the three coordinate variables x, y, and z of a scalar quantity whose value varies from point to point, a graded difference in physiological activity along an axis (as of the body or an embryonic field), change in response with distance from the stimulus