My suggestion is to give your friends a CC history book.
It was known as The Way, first. See Acts 9
Code:
1 Now Saul, still breathing murderous threats against the disciples of the Lord, went to the high priest 2 and asked him for letters to the synagogues in Damascus, that, if he should find any **men or women who belonged to the Way, ** he might bring them back to Jerusalem in chains.
Earliest Use of the Name “Catholic Church”
The early Church - the Church founded by Christ as promised in Matthew 16:18 -
was that which was originally known as the Way (cf. Acts 24:14). Later, those
who followed Christ began to be called Christians beginning at Antioch (cf. Acts
11:26).
As early as 107 A.D., that same group was referred to as the “Catholic Church”.
In a letter to the Church of Smyrna, Ignatius of Antioch wrote, “You must all
follow the bishop as Jesus Christ follows the Father, and the presbytery as you
would the Apostles. Let no one do anything of concern to the Church without the
bishop. Wherever the bishop appears, let the people be there; just as wherever
Jesus Christ is, there is the Catholic Church.” (Letter to the Smyrnaeans, A.D.
107, [8,1])
Notice that Ignatius does not introduce the term “Catholic Church”; instead he
uses it in a manner suggesting that the name was already in use and familiar to
his audience. This further suggests that the name, Catholic Church, had to have
been coined much earlier in order to have achieved wide circulation by the time
of this writing. That means that the Christian assembly was probably calling
itself the “Catholic Church” during the lifetime of the last Apostle, John, who
died near the end of the first century.
The Catholic Church began with Peter and the Apostles and continued without
interruption or cessation through their disciples (Ignatius, Irenaeus, Polycarp,
Clement, Justin Martyr, etc.) down to the present day.
As a side note, it is interesting that the believers in Antioch coined both
terms still in use today: “Christian” and “Catholic Church”.