CCC 830 The word “catholic” means “universal,” in the sense of “according to the totality” or “in keeping with the whole.” The Church is catholic in a double sense:
First, the Church is catholic because Christ is present in her. “Where there is Christ Jesus, there is the Catholic Church.”¹ In her subsists the fullness of Christ’s body united with its head; this implies that she receives from him “the fullness of the means of salvation”² which he has willed: correct and complete confession of faith, full sacramental life, and ordained ministry in apostolic succession. The Church was, in this fundamental sense, catholic on the day of Pentecost³ and will always be so until the day of the Parousia.

1 St. Ignatius of Antioch, Ad Smyrn. 8,2:Apostolic Fathers,II/2,311.
2 UR 3; AG 6; Eph 1:22-23.
3 Cf. AG 4.