Brand New Wood Turner - Question about Centers

[hollislocke]

At this very moment, I can't remember the model of my lathe. I just picked it up and it is in a different garage as I don't have room. I'll be able to post it tomorrow.

I bought it used and it turns out to not have any centers. Now, as I have been looking online, I've seen various numbers such as 5/8 and 1". What is this number referring to? For example, a 4 prong drive center that comes in two sizes. Is the 5/8 or 1 inch the width of the prongs? Does it refer to some other size?

If I'm looking for a tapered center, are they pretty much all the same?

I'm new enough that I might be asking the wrong questions, so please feel free to answer the correct questions for me. :)