Where have today’s religious titles come from? For instance, why the difference in titles from father, preacher, priest, etc. I’m especially curious about how the title of Pope and Cardinal came about.
Thank You.
Well, Pope comes from the word for father- “papa”. Cardinal comes from a word meaning “first” or “principal”.
Let’s see:
The early church was run by overseers, assisted by elders, with helpers, well, helping. Only because they spoke Greek, it was run by episkopoi assisted by presbuterioi helped by diakonoi, and those evolved into bishops, presbyters, and deacons. Presbyter then went through another transmogrification to priest, passing by Prester, as in Prester John, along the way.
The chief honchos among the bishops and deacons became archbishops and archdeacons respectively.
The five leading bishops, in sees founded by apostles or evangelists, became Patriarchs, which translates loosely as “first fathers.” Of them, the acknowledged leader and the only one in the West was the Patriarch of Rome, who became Father, Papa, of the church as a whole, hence Pope. (The Coptic Patriarch of Alexandria is also Pope, for the same etymological reason.)
A priest was named to be the “shepherd” for an individual parish church – but, speaking Latin, he became its “shepherd” in Latin, or pastor.
The leading figures supporting the Pope became the hinge people through whom he connected with the church as a whole. Hinge as an adjective in Latin is cardinalis.
The polite way to reference the clergy person having patriarchal authority over a local church was to call him either Father or Pastor.
Religious orders are an entirely different ball of wax, and the titles there would require at least as long a post. But in general they’re seen as communities corresponding to families, in which the members are Brothers and Sisters of each other and of the people whom they serve. More on this only if desired.
In Latin, the pope is referred to as Pontifex Maximus, a title borrowed from the high priest of the Roman pagan religion. It means “greatest bridge builder”.
Well, if you’re offering go ahead and make me all that much more enlightened. Like I haven’t been enlightened enough 
Thanks once again; and may I say that the reason I love Straight Dope so much is the way everyone on here answers the questions so thoroughly and quickly. You all deserve some mad props!