any process or change taking place through a series of stages, by degrees, or in a gradual manner.

a stage, degree, or grade in such a series.

the passing of one tint or shade of color to another, or one surface to another, by very small degrees, as in painting or sculpture.

the act of grading.

ablaut.

Geology . the leveling of a land surface, resulting from the concerted action of erosion and deposition.

noun

arrangement , calibration , change , degree , difference , distinction , divergence , grade , grouping , level , mark , measurement , modification , notch , nuance , ordering , place , point , position , progression , rank , scale , sequence , series , shade , sorting , stage , succession , variation , hue , tinge , tint