Meaning

noun (Roman Catholic Church) an antiphon (usually from the Book of Psalms) immediately after the epistle at Mass

adjective proceeding in small stages

adjective (of a topographical gradient) not steep or abrupt

originFrom Medieval Latin graduālis, from Latin gradus (“step”), from Proto-Indo-European *gʰradʰ-, *gʰredʰ- (“to walk, go”). Cognate with Gothic 𐌲𐍂𐌹𐌸𐍃 (griþs, “step, grade”), Bavarian Gritt (“step, stride”).

Etymology from Wiktionary, CC BY-SA 3.0