This is being nitpicky, but dioceses can be quite a bit bigger than a metropolitan area. Here is a mapof the diocese in the U.S. Some of them are very large.
Ditto the Scottish Episcopal Church I believe.
In the Catholic Church, you’ll often find a rector in the bishop’s home church, the cathedral. If the cathedral is also the parish church, the bishop is the pastor of that parish, but since he obviously has other duties that would prevent him from serving the pastoral needs of the faithful in that parish, it’s common to appoint a priest to serve as the rector of the cathedral and the de facto pastor for that parish.
Similarly, a priest in charge of a non-diocesan church, or of a basilica, in an area will be called a rector. Canon law provides that seminaries and Catholic universities also have rectors.
Depends on how you define size. The one I’m in, the Diocese of Helena, covers half of one of the largest states in the country, but only about a half-million people. So in terms of population, it is actually comparable to a smallish metropolitan area.
By contrast, in Anglicanism, the person who has the living in the cathedral is normally called the Dean, as the senior priest of the diocese. In fact, I don’t think that the Bishop is considered to be the parish priest of the cathedral - that’s the function of the Dean.
This point illustrates the difference between the sacramental nature of a bishop, and the administrative duties. Once ordained bishop, a person is a bishop for life, just as a priest is a priest for life. However, a bishop can be relieved of his position as administrative head of the diocese, or can retire or resign, just as a priest does not need to have a parish to be a priest.
Indeed. Some Australian dioceses are very large.
This is a thread I intended to start, but with reference to C of E (Anglican) ranks as read in all too many Victorian novels (I love laying down with a good Trollope). I suspect some of the answers will be the same, but:
Archdeacon
Chaplain
Curate
Deacon
Dean
Padre
Parson
Pastor
Priest
Rector
Verger
Vicar
When I was still going to church - in the late '70s - it was still common for a parish to have more than one priest, but I never heard the term vicar. So it wasn’t used all that much even then.
I didn’t realize there was that much of a shortage of priests. That’s kinda sad. 
Growing up a Catholic boy in St. Louis in the 60s, I never heard/read the term “vicar” except in the context of the Pope’s title as “Vicar of Christ”. The head priest at a Catholic church was called the “pastor”, and the others were “assistant pastors” (maybe the “second in command” would be called an “associate pastor”; I don’t remember that usage, myself, but anything’s possible).
As long as I’m piping up here, I’m surprised that toadspittle didn’t ask about “monsignor”, an honorific title for senior priests that was given out like candy (or so it seemed) in the Archdiocese of St. Louis when I was younger. Been ages since I read A Canticle for Leibowitz, but I’m a bit suprised that one didn’t work its way into the books.
Cheers,
bcg
The meaning of the word as used by the Church of England is much more complicated than that.
As others have explained, the Catholic Church did use it to mean a priest who performed the parochial duties on behalf of the incumbant. In pre-Reformation England this was usually because the living was held by a monastery - the monastery would receive the income from the parish (the tithes etc.) and would then make arrangements to ensure that a priest, the ‘vicar’, nominated by them carried out the actual work.
However, at the Dissolution of the Monasteries, those rights, along with all other monastic properties, were confiscated by the Crown. And the Crown then cashed in on them by selling off those rights, almost always to local lay landowners. The tithes would be paid to that landowner, who would also have the right to nominate the parish priest, whose salary he would then pay. The person to whom the ‘vicar’ was thus deputising was therefore usually a layman (or, very occasionally, a laywoman). A ‘rector’, in contrast, was a parish priest who held the living, including its income, in his own right. A deputy employed by either a vicar or a rector was instead a ‘curate’.
This distinction between a vicar and a rector still exists in England. But the rights of the lay patrons have been largely abolished, so the distinction has almost no practical significance. As a result, ‘vicar’ now tends to be used instead as an informal, generic term for any Anglican clergyman.
I’ll take a shot at the list.
Archdeacon - not an additional ordained position, but a title for a senior priest in the diocese who has been given additional administrative duties; (similar usage to “Archbishop”, which doesn’t carry any additional sacramental duties, but has additional administrative duties).
Chaplain - this could be any priest who is employed to give spiritual services, rather than being a parish priest. The king, the nobility, and other wealthy personages might employ their own private chaplain. Chaplains could also be attached to army units or to naval ships, to provide spiritual services to the officers and men.
Curate - a junior priest, employed by a parish in addition to the incumbent. Usually someone recently ordained and hopeful of eventually obtaining a parish of his own. The pay was poor, so in novels it’s common to see the theme that a young lady couldn’t be allowed to marry a mere curate, who would barely have enough to live on for himself, let alone support a family. The young couple would have to wait until he obtained his own parish.
Deacon - as outlined in the previous posts, the deacon is the first step in the ordained orders. There’s a difference here between the Anglican and Roman Catholic churches. The Roman Catholic church had minor ordained positions, leading up to the ordination of a priest, but the Anglican church abandoned those minor ordained positions at the Reformation, so the position of deacon is now the starting point for ordination. For more on the diaconate, see this earlier thread: Diocanate – huh?
Dean - as discussed earlier, this is the parish priest of a cathedral, and is called the Dean because he is the senior priest of the diocese by virtue of that position.
Padre - one way to refer to a priest informally; often associated with military chaplains.
Parson - another informal way to refer to any member of the clergy, not just Anglican clergy.
Pastor - a clergyman who is focused on providing spritual services, rather than other types of ministry, such as an academic. The concept of the clergy as pastor is not restricted to Anglicanism, but is common in Christianity. It comes from Jesus’ use of the metaphor of the pastor protecting the flock of sheep to represent the role of the church. See John 21: 15-17, with his commandment to Simon Peter (and by extension, all the apostles), to “feed my sheep.”
Priest - the main ordained position within the church. Priests are able to perform all sacraments except ordination and confirmation. Note that the use of the term “priest” has varied considerably over the years in the Anglican tradition. Those Anglicans who emphasise the Protestant aspects of the church’s traditions may be more comfortable with terms such as “minister” rather than “priest”, while those Anglicans who emphasise the Catholic aspects tend to be more ready to use the term “priest.”
Rector - see earlier posts, including APB’s post.
Verger - a lay person employed or appointed by the parish to assist in the conduct of services. See the wiki article on vergers. Often used in Victorian literature to represent a person of solid worth in the community, but perhaps tending to the staid and pompous.
Vicar - see earlier posts, including APB’s post.
That is interesting, because in RCC practice, we also have Deans. A bishop may group several geographically contiguous parishes together as vicariates forane, or “deaneries.” Each such group is headed by a vicar forane, normally called a Dean. So a diocese may have, say, six deaneries and six deans.
An archdeacon is a high-ranking priest who works for the diocese as the bishop’s #2 man for smaller and rural parishes, of which every diocese has a few. In other words, the Bishop need not be on top of what’s going on with St. James’s Church in East Bumbleflock (membership 20), because the Archdeacon’s job is to be aware of that, and the other 30 parishes of about the same size.
A Chaplain is someone charged with the religious care of some group other than a parish church. 98% of the time it refers to a commissioned military officer who is a clergyman, whose job it is to provide services and counseling for soldiers/sailors/airmen of his faith. But fraternal orders, Congress, prisons, etc., also have chaplains.
Curate literally means any clergyman with a ‘cure of souls’ – i.e., any parish priest or deacon. More commonly, however, it is the term used for a Rector’s assistant, technically the Assistant Curate of the Parish.
Deacon in churches ranging from Methodist to Orthodox, including Catholic and Anglican, is the lowest rank of clergyman, able to preach, baptize, and celebrate marriages, but not to celebrate the Eucharist (Mass) – though there is a procedure to be followed if a bishop or priest is not available but a deacon is. In many Protestant traditions, however, a Deacon is a layman whose job it is to serve on a board that provides for the church’s charitable activities – ideally both giving out money as needed (for a missionary or for relief in a disaster area) and also reaching out to the poor and needy of the church.
A Dean is two things – either (A) the senior clergyman in a Deanery – a subdivision of a diocese – with some special responsibilities to the Bishop (for example, if the Bishop is confirming a bunch of people from a number of small parishes, the Dean sets it up; or (B) the chief clergyman, under the Bishop, of the Cathedral church (of which the Bishop is ex officio the actual chief clergyman, but somebody has to be in charge of the day-to-day services and outreach of the cathedral while the bishop is off doing other things, and that’s the Dean.
Padre is Spanish for “Father” and is a traditional form of address for a military Chaplain,. sometimes jocularly used of other clergymen.
Parson equals Pastor – the ordained guy who’s in charge of the local church. I don’t know if it’s a formal title in any church, but it was a very common usage for parish clergy, especially in protestant churches.
Pastor is the man who provides pastoral care to a congregation – i,.e., the chief priest or minister of any parish church. Anglicans tend not to use the term, but both Catholics and Protestants do. It’s also the title for an ordained Lutheran clergyman, whether or not he serves a parish.
Priest was defined above. It derives from Greek presbuterios, meaning elder. Note that Methodists keep the three ranks of clergy, but call the middle rank, the one most clergy are, Elders rather than Priests. Presbyterian usage of the term Elder is sufficiently bizarre that I’ll leave it for a Presbyterian to explain, because I know I’ll bollix it,.
A Rector is a Priest who was called by (Anglican) or assigned to (Catholic) a self-supporting parish church, though Catholics prefer the use of Pastor. A Rector can also be the headmaster of a religious school or a few other specialized usages.
As Northern Piper noted, Vicar is used for a clergyman who is in charge of a parish but not its Rector. It was formerly the use in American Episcopal churches for the priest assigned to a mission, but today the term Priest In Charge is more common.
Verger is not a clergyman at all – he’s the guy in charge of the physical structure of the church building, with a couple of special ceremonial roles to play in formal festival services (like carrying the Bishop’s Mace – why does a bishop have a mace? Dunno – but if he does, and there’s a Verger, it’s the Verger’s prerogative to carry it.)
By the way, religious orders:
They’re made up of people who feel a calling to live in celibacy within a community of like-minded people. There’s a single vow, of poverty, chastity, and obedience, not three separate vows.
Monks and nuns are cloistered in “contemplative orders”, living lives devoted to prayer and work, with little contact with the rest of the world. Most “monks” and “nuns” people encounter are from “servant orders” and are Brothers and Sisters, pedantically not called monks and nuns in the proper use (though most people do anyway).
Franciscan and Dominican males are friars, not monks – their proper task is to preach the Gospel and minister in humility. Because of that special call, and the idea of itinerancy rather than life within a monastery, they make the distinction.
Same in American Anglicanism – see my post. A diocese with a cathedral (most of 'em, but mine doesn’t) will have a Dean of the Cathedral; most dioceses are broken into Deaneries (sometimes called Districts) with a Rural Dean for each (even if it’s an urban area, he’s a ‘Rural Dean’ to distinguish him from the guy in the Cathedral).
So, whats a monsignor?
Basically, it’s an honorary title given to certain senior Catholic priests. The Wikipedia article:
has a pretty good breakdown of the various honors which entitle the bearer to take the title “Monsignor”. It’s all rather complex, as you might imagine.
Cheers,
bcg
It is an honorary title bestowed on a priest as recognition of his service.
It represents no level of authority or placement in the hierarchy, (either of orders or administration). It just means that his bishop thought he was doing a good job over a number of years and figured that he should be recognized as having done so and sent his name off to the Vatican for recognition. Being recognized as monsignor permits the priest to wear red piping and some other symbols on his clerical gear, but that is about it, Interestingly, depending on which specific honor is requested for him, a monsignor’s status may be tied directly to the sitting pope who normally authorizes his title and the title goes away if the pope dies. Other versions are permanent and stay in effect even if the pope dies.
The most obvious being, based on the monsignori of my Catholic youth, a huge, honkin’ purplish-red sash around the waist of his cassock.
I was young back then; I impressed easily. 
Cheers,
bcg