Gradual means happening slowly, step by step, not all at once. A gradual change, gradual improvement, gradually better.
The step-by-step part is the point: gradual describes a process with stages rather than merely a slow one. Gradually is one of the commonest adverbs in English and is used constantly to describe recovery and decline. Note the difference from sudden; and that gradual comes from the Latin gradus, a step, which also gives grade, degree and gradient.
1adjectivegradualHappening slowly, step by step.
“There has been a gradual rise in temperature over the last century.”
gradual is a quality of slow progression.
Medieval Latin gradualis comes from gradus, a step. Grade, degree, gradient and progress come from the same stepping.
Proto-Indo-European
*gʰradʰ-
Latin
gradus — step
Medieval Latin
graduālis
English, today
gradual
Built from
From Medieval Latin graduālis, from Latin gradus (“step”), from Proto-Indo-European gʰradʰ-, gʰredʰ- (“to walk, go”). Cognate with Gothic 𐌲𐍂𐌹𐌸𐍃 (“step, grade”), bar Gritt (“step, stride”).
Etymology from Wiktionary, CC BY-SA