We profess at each Mass, our belief in a church that is one, holy, catholic, and apostolic.
What does it mean to say that our church is "catholic"?
St. Ignatius first used the term "catholic" or "universal" to describe Christ's church in 107, and the term was likely old back then. (Pillar of Fire, Pillar of Truth; p. 5)
The Chuch is God's gift to the whole world. It is the Body of Christ, and we all know what John wrote about God's gift of Christ (John 3:16). God's only Son created one church for all of us. If there is one God, then there is one faith, then there is one church that He founded for all. After that foundation, God sent His Holy Spirit - one Spirit - to all of us as guide and protector. (John 15:26) That is universality - catholicity - that God loves all of us, cares for all of us, and provides for all of His children together.