Etymology

Noun

1. A slope or incline.
2. A rate of inclination or declination of a slope.
3. Of a function y = f(x) or the graph of such a function, the rate of change of y with respect to x, that is, the amount by which y changes for a certain (often unit) change in x.
4. The rate at which a physical quantity increases or decreases relative to change in a given variable, especially distance.
5. A vector operator that maps each value of a scalar field to a vector equal to the greatest rate of change of the scalar. Notation for a scalar field φ: $\backslash nabla$φ

Noun

1. gradient; a vector operator