Gradation

[grey-dey-shuh n] /greɪˈdeɪ ʃən/

noun
1.
any process or change taking place through a series of stages, by degrees, or in a gradual manner.
2.
a stage, degree, or in such a series.
3.
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.
4.
the act of .
5.
.
6.
Geology. the leveling of a land surface, resulting from the concerted action of erosion and deposition.
/ɡrəˈdeɪʃən/
noun
1.
a series of systematic stages; gradual progression
2.
(often pl) a stage or degree in such a series or progression
3.
the act or process of arranging or forming in stages, grades, etc, or of progressing evenly
4.
(in painting, drawing, or sculpture) transition from one colour, tone, or surface to another through a series of very slight changes
5.
(linguistics) any change in the quality or length of a vowel within a word indicating certain distinctions, such as inflectional or tense differentiations See ablaut
6.
(geology) the natural levelling of land as a result of the building up or wearing down of pre-existing formations
n.

1530s, “climax,” from Middle French gradation (16c.) and directly from Latin gradationem (nominative gradatio) “ascent by steps, a climax,” noun of action from gradus “step, degree” (see grade). Meaning “gradual change” is from 1540s. Related: Gradational.
gradation
(grā-dā’shən)