gradational (adj.)

1530s, "a climax;" 1670s, "orderly arrangement or succession," from French gradation (16c.) and directly from Latin gradationem (nominative gradatio) "ascent by steps; a climax," noun of action from gradi "to walk, go, step" (from PIE root *ghredh- "to walk, go"). Meaning "gradual change" is from 1540s.

suffix forming adjectives from nouns or other adjectives, "of, like, related to, pertaining to," Middle English -al, -el, from French or directly from Latin -alis (see -al (2)).