A choral book containing the Ordinary of the Mass, viz., Kyrie, Gloria, Credo, Sanctus, Agnus Dei, with the Antiphons, Asperges me, or Vidi Aquam which precede the High Mass on Sundays.
The book takes its name from the first number, the Kyrie.
At first the Kyriale formed a part of the Graduale which contains the Propers of the Mass, but after the Middle Ages we find it in a separate book called the Kyriale.
Since the Kyriale contains the Ordinary of the Mass in easy melody, it is customary for the promotion of congregational singing to scatter Kyriales in the pews.
The latest edition, the Editio Vaticana, was published at the command of Pius X.
New Catholic Dictionary