decrees of Roman Pontiffs and Congregations
These are largely legislative enactments, the former found in papal Constitutions, Apostolic letters, Apostolic epistles, and Motu Proprios; the latter in the decrees proper of the respective Congregations.
The word decree is also used by the Church today in a non-legislative sense.
Hence the Code on the one hand speaks of the decrees of general councils, of national and provincial councils, and even diocesan synods; on the other hand, of judicial and non-judicial decrees.
Judicial decrees are all the rulings of an ecclesiastical court not comprised in incidental and final decisions.
Non-judicial decrees vary from the regulations made in an episcopal visitation to the formal acts removing or transferring a pastor for the greater good of souls.
The Roman Congregations, too, issue non-legislative decrees.
For instance, the preliminary determinations in a process of canonization are made through decrees by the Congregations of Rites, the pope ratifying; so also are books condemned oy the Holy Office.
But the Congregations now refrain from using the term decree when answering a query and designate the responses given either all dubia or declarationes.
New Catholic Dictionary