Profession definitions

[JubileeLee]

I'm trying to use the add form to add a couple of models I can't see a listing for on the site, but I don't really know what profession category to put them in. Could someone tell me what the dividing lines are for being listed as an "adult model", "centerfold", "porn star" or "supermodel" please? I'm assuming supermodel is someone mainstream famous, but not sure of the others. Isn't a centerfold an adult model anyway? It's a little confusing.