Gradual
The Gradual (Latin: graduale or responsorium graduale) is a chant or hymn in the liturgical celebration of the Eucharist for many Christian denominations. In the Tridentine Mass it is sung after the reading or chanting of the Epistle and before the Alleluia, or, during penitential seasons, before the Tract. In the Mass of Paul VI the gradual corresponds to the Responsorial Psalm. There is the option to replace this psalm with the gradual, but its use is extremely rare. It is part of the Proper of the Mass.