What does “catholic” mean? The word “catholic” means “universal” in pertaining to “according to the totality” or “in keeping with the whole.” The one church which Christ founded and makes holy by His presence has now become the universal faith. Fr. Hardon explains “In general, today the term ‘Catholic’ refers to those Christians who profess a continued tradition of faith and worship and who hold to the Apostolic succession of bishops and priests since the time of Christ.” [1]
 
The Catechism of the Catholic Church views the term “catholic” in two ways:
 
- “First, the Church is catholic because Christ is present in her. ‘Where there is Christ Jesus, there is the Catholic Church.’ 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’ 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 Pentecost and will always be so until the day of the Parousia.” [2]
 
- “Secondly, the Church is catholic because she has been sent out by Christ on a mission to the whole of the human race: All men called to belong to the new People of God. This People, therefore, while remaining one and only one, is to be spread throughout the whole world and to all ages in order that the design of God’s will may be fulfilled: he made human nature one in the beginning and has decreed that all his children who were scattered should be finally gathered together as one…The character of universality which adorns the People of God is a gift from the Lord himself whereby the Catholic Church ceaselessly and efficaciously seeks for the return of all humanity and all its goods, under Christ the Head in the unity of his Spirit.” [3]
 
Catholic Churches throughout the world come in many sizes, shapes, and names. However, just because one person attends St. John Vianney Catholic Church and another attends Holy Trinity Catholic Church, they still belong united to the one universal Church. How can this be? “Let us be very careful not to conceive of the universal Church as the simple sum, or … the more or less anomalous federation of essentially different particular churches. In the mind of the Lord the Church is universal by vocation and mission, but when she puts down her roots in a variety of cultural, social, and human terrains, she takes on different external expressions and appearances in each part of the world.’ The rich variety of ecclesiastical disciplines, liturgical rites, and theological and spiritual heritages proper to the local churches ‘unified in a common effort, shows all the more resplendently the catholicity of the undivided Church.’” [4] Think of it this way: if we were to go to a different country and celebrate Mass, it may be different language or there may be a different way of presenting the gifts. However, it is still united in Christ with the same sacrifice in both Liturgy of the Word and Liturgy of the Eucharist.
 
How is a diocese of the Catholic Church similar to the hierarchy of the Magisterium? The head of the church, the Bishop of Rome, along with all the other Bishops comprise the Magisterium. Similarly, we all belong to a particular church, which is in a diocese under the direction of an ordained bishop, who was ordained through the apostolic succession. There are thousands of dioceses around the world and all are fully catholic through the communion the Church of Rome. [5] “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.” [6]
 
What does “catholicity” mean? Catholicity is defined as the “Universality of the Church founded by Christ. In the Nicene Creed the Church is said to be ‘one, holy, catholic, and apostolic.’ The Church’s catholicity is first of all spatial, on account of her actual extension over the whole earth. This kind of catholicity may be actual, when the Church is actually extended everywhere; it is virtual in that Christ’s intention was to have the Church present among all peoples. Actual catholicity is said to be physical if it embodies all persons of the earth, even if not literally every individual. It is moral if it includes only the greater part of them. Although moral catholicity suffices for the Church’s universality, yet it is Christ’s will that the Church constantly endeavor to extend. The ideal toward which the Church strives is physical catholicity. A common position among apologists holds that moral catholicity demands that the Church extend over the whole earth simultaneously. Thus after a certain time of development, moral catholicity will be realized and from that time on is to be perpetuated.” [7]

[1] Hardon, Modern Catholic Dictionary pg. 87
[2] CCC 830
[3] CCC 831
[4] CCC 835
[5] Cf. CCC 834
[6] CCC 833
[7] Fr. Hardon, Modern Catholic Dictionary pg. 88