The term 'Catholic' most often refers to the members, beliefs, and practices of the Catholic Church (Roman Catholic Church) that is in full communion with the Pope (The Bishop of Rome and Christ's vicar on Earth). The Church sees its authority as deriving from Matthew 16:18 (You are Peter and upon this rock I will build my Church). Saint Peter went on to become the Bishop of Rome from 30-64, was succeeded by Pope Linus and so on all the way down to Pope Benedict XVI. The doctrine of Apostolic Succession, by which each bishop is consecrated by other bishops, is important in linking the Church all the way back to the original twelve apostles of Christ.
|Bless me sister cause I'm about to sin!|
The current Pope (Benedict XVI), oversees one billion adherents who are about half the estimated 2.1 billion Christians in the world today and who make up what is by far the largest Christian denomination. The rest are splitters and dirty heretics (but still Christians) who just don't feel the Pope and his church has a clue. At various times over the centuries these non-catholic Christians have decided that Catholicism is corrupt, depraved and elitist and have gone their own way - since they have their own ideas about how God wants to be worshipped. This has involved much unpleasantness since the Catholic Church took challenges to its power very seriously. See Religious wars, Catholic section.
Fortunately we in the civilized West NOW don't feel the need to blow each other up just 'cause the sacramental wine doesn't always get passed left to right. Indeed, in some cases Catholics are even seen as fantasy figures - especially young Catholic girls, who invariably turn out to be twisted nymphomaniacs with a nun fetish. [Or is that just me?] ... (Nope, me to! Nunsploitation movies rule although my catholic mate says nuns aren't like that. Spoilsport!)
Note: Even the term Catholic is laid claim to by other Christian denominations, including the Eastern Orthodox Church and those Protestant Churches possessing the historic episcopate (bishops). ["Do you possess the historic episcopate"? "Oh yeah, I've got one of those, but it's in my other jacket"]