The difference between a church and a cathedral
The difference between a church and a cathedral is something that confuses most people. In fact the two terms are largely used interchangeably these days. The general assumption is that a cathedral is just a large church, this is not actually the case. There is a very specific criteria that a church must meet in order to be considered to qualify as being a cathedral.
The difference between a church and a cathedral is simply that a cathedral is a church that also serves as the seat of the bishop. Normally it is the main church of the dioceses. In most cases the cathedral will be the largest and most impressive church in the dioceses but this is far from always the case. While the difference between a church and a cathedral is fairly simple to understand there are some factors that tend to make things a little bit confusing. The result is that you will come across situations where a building is called a cathedral even though it technically isn't one.
The main reason that you will come across churches that are called cathedrals even when they aren't is the result of the protestant reformation. Many of the new protestant sects did not take on the hierarchical nature of the Catholic Church. That means that there are no bishops in these sects. In many cases however they took over the Catholic Churches in the area where they were active. In cases where one of these churches was a cathedral they tended to retain the name even though it no longer was a cathedral as there was no bishop.
The other reason that you will find that church referred to as a cathedral even though there is no bishop is in cases where the bishop has moved to another church. Often the church that lost the bishop does not want to downgrade their name so they continue to refer to it as a cathedral. This can cause some confusion since it usually means that there is more than one cathedral in the dioceses.
Most people just assume that a large and fancy church is a cathedral, this is not the case. Certainly in most cases the bishop will choose to have his seat at the largest church in the dioceses but this is far from always the case. Therefore you cannot just assume that because something is called a cathedral it will be a large church, although usually you would be right. Ultimately it really doesn't matter what the church is called. The two terms are used almost interchangeably these days so it is really only a stickler who is going to worry about the difference. Nevertheless it is one of those things that is nice to know when you are visiting churches and cathedrals.