Spád

Spád is a term used in Slovak and Czech meaning slope, gradient, or incline. It describes how steep a surface or a path is. In geography and geomorphology, spád is the steepness of terrain, defined as the vertical change over a given horizontal distance. It can be expressed as a percentage (rise over run) or as an angle. A higher spád means faster runoff and steeper slopes, influencing erosion, drainage, and land use planning.

In civil engineering and construction, spád refers to the designed incline of surfaces such as roofs, roads, or drainage channels. Roof spád ensures proper shedding of water; road spád affects drainage and accessibility; drainage spád governs the flow in pipes and channels. Design codes specify minimum and maximum spád values depending on material, climate, and use.

In mathematics, spád denotes the slope or gradient of a function. For a real-valued function y=f(x), the spád at a point is the derivative f'(x). In several variables, the gradient ∇f is the vector of partial derivatives and points in the direction of steepest ascent.

The term is used in everyday language to refer to inclined surfaces or hills. Etymologically, spád derives from a Slavic root related to falling or slanting, and is cognate with related terms in other Slavic languages.