Grade (slope)

tangent of the angle of a surface to the horizontal
For other uses see: Gradient (disambiguation)

The grade (or gradient) of a road or railway line is a measure of its steepness. It may be expressed as a percentage or in other ways. For example, a gradient of 1% may also be expressed as 1 in 100. This means that the road rises or falls by 1 metre for every 100 metres of forward travel.

Road sign indicating a 20% upward gradient
Railway gradient post showing a change from level track to a downward gradient of 1 in 1026