There was ever only the Catholic Church. If "catholic" just meant universal and didn't distinguish a particular Church, it doesn't actually mean anything. As one example, the Edict of Thessalonica (380) recognises the Trinitarian faith as belonging to Catholic Christians and mentions the pope at the time. If it meant "universal Christians", then it would include Arians, which was the opposite of what it was trying to say.yes, the adjective catholic means universal:
However Catholic is a proper noun usually referencing (in this forum) the Catholic Church in Rome under the authority of a Pope.
At its best. the Catholic Church was once part of the catholic church.