grade (as a verb, in technical sense)

grade (Am-Heritage):

4. To level or smooth to a desired or horizontal gradient: 

• bulldozers graded the road.
  

grade (Am-Heritage-Science): 

1. The degree of inclination of a slope, road, or other surface.

cf. gradient (OALD): 

(1) the degree to which the ground slopes, especially on a road or railway: a steep gradient; a hill with a gradient of 1 in 4 (or 25%) 

(2)(technical) the rate at which temperature, pressure, etc. changes, or increases and decreases, between one region and another