§887
Creed › … › Paragraph 4. Christ's Faithful - Hierarchy, Laity, Consecrated Life
The episcopal college and its head, the Pope
Neighboring particular Churches who share the same culture form ecclesiastical provinces or larger groupings called patriarchates or regions. 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."
Source: Catechism of the Catholic Church (Vatican.va)