CCC 833 The phrase “particular Church,” which is first of all the diocese (or eparchy), refers to a community of the Christian faithful in communion of faith and sacraments with their bishop ordained in apostolic succession.1 These particular Churches “are constituted after the model of the universal Church; it is in these and formed out of them that the one and unique Catholic Church exists.”2
1 Cf. CD 11; CIC, cann. 368-369; CCEO, cann. 171,1; 178; 311,1; 312.
2 LG 23.