[grad.u.al] n, often cap [ME, fr. ML graduale, fr. L gradus step, fr. its being sung on the steps of the altar] (15c) 1: a book containing the choral parts of the Mass
2: a pair of verses (as from the Psalms) proper after the Epistle in the Mass
[2]gradual adj [ML gradualis, fr. L gradus] (1692) 1: proceeding by steps or degrees
2: moving, changing, or developing by fine or often imperceptible degrees -- grad.u.al.ly adv -- grad.u.al.ness n