gradient

1. A slope or incline.
2. A rate of inclination or declination of a slope.
3. The ratio of the rates of change of a dependent variable and an independent variable, the slope of a curve's tangent.
4. The rate at which a physical quantity increases or decreases relative to change in a given variable, especially distance.
5. A differential operator that maps each point of a scalar field to a vector pointed in the direction of the greatest rate of change of the scalar. Notation for a scalar field φ: ∇φ
6. A gradual change in color; a color gradient; gradation.

الجمع gradients