How childish our answer is, and wrong too. Are you even reading any of this?
Kato = According to
Holos = The Whole
In the book of Acts, "ekklesia kath holos," which is translated "the Church throughout all," is where the word "katholos" comes from.
Ἡ μὲν οὖν ἐκκλησία καθ' ὅλης τῆς Ἰουδαίας καὶ Γαλιλαίας καὶ Σαμαρείας εἶχεν εἰρήνην, οἰκοδομουμένη καὶ πορευομένη τῷ φόβῳ τοῦ κυρίου, καὶ τῇ παρακλήσει τοῦ ἁγίου πνεύματος ἐπληθύνετο.
The Catholic Church spans the globe. The successor of Peter is the Bishop of Rome, and that is why to church at Rome is predominent.