CCC 887 Neighboring particular Churches who share the same culture form ecclesiastical provinces or larger groupings called patriarchates or regions.1 The bishops of these groupings can meet in synods or provincial councils. “In a like fashion, the episcopal conferences at the present time are in a position to contribute in many and fruitful ways to the concrete realization of the collegiate spirit.”2
1 Cf. Apostolic Constitutions 34.
2 LG 23 # 3.