“ As a substantive, “gradual” (Med. Lat. graduale or gradale) is used of a service book or antiphonal of the Roman Catholic Church containing certain antiphons, called “graduals,” sung at the service of the Mass after the reading or singing of the Epistle. This antiphon received the name either because it was sung on the steps of the altar or while the deacon was mounting the steps of the ambo for the reading or singing of the Gospel. ”