The rate of descent or ascent (steepness of slope) of any topographic feature, such as streams or hillsides.

A vector obtained from a real function f (x₁, x₂,...,x_n ) whose components are the partial derivatives of f; this measures the maximum rate of change of f in a given direction.

A slope expressed in feet per mile as a ratio of the horizontal to the vertical distance; for example, 40:1 means 40 feet horizontally to 1 foot vertically.