(1):
(n.) A series of steps.
(2):
(n.) An antiphon or responsory after the epistle, in the Mass, which was sung on the steps, or while the deacon ascended the steps.
(3):
(n.) Proceeding by steps or degrees; advancing, step by step, as in ascent or descent or from one state to another; regularly progressive; slow; as, a gradual increase of knowledge; a gradual decline.
(4):
(n.) A service book containing the musical portions of the Mass.