i'm not sure why or how we call our church and ourselves is such a big deal..
the link tells about how RCC got her name, since you asked for it.
there were other Catholics who didn't tie up with the Roman Church. just to have a distinction.
the term Catholic is the term used for believers of Christ Jesus.
so it should follow that the church in Rome should be called Roman Catholics. is there something wrong with that?
Protestants have more or less 33,000 denominations each having their own church name.
Regarding Catholicism and Apostolic order in general:
The earliest recorded evidence of the use of the term "Catholic Church" is the Letter to the Smyrnaeans that Ignatius of Antioch wrote in about 107 to Christians in Smyrna. Exhorting Christians to remain closely united with their bishop, he wrote: "Wherever the bishop shall appear, there let the multitude [of the people] also be; even as, wherever Jesus Christ is, there is the Catholic Church.
source:
History of the term "Catholic" - Wikipedia, the free encyclopedia
Ignatius of Antioch:
Ignatius of Antioch - Wikipedia, the free encyclopedia
of course you cannot see the word Catholic in the Bibles we have today
as Catholic is not an english word, the term is derived from Greek
which how originally biblical accounts were written.
Catholic simply refers to the whole believers of Jesus, the whole Christian church,
Roman Catholicism simply points out to the Catholic Church in Rome
through the apostolic succession, believed to have been established by Jesus in commanding St. Peter.