Whats a global moderator?

Ok, so I have seen Global Moderators on several sites before, but what are they? Are they the same as a Moderator?

Global Moderaters are Site Staff that are Moderaters, except they do some extra work. (Well, atleast on my site.) So, in terms yes they are the same as Moderaters.

Well, Global Moderators are people below co-admins.They moderate all the forums and are head of normal moderators.
While people, having the moderator post moderate several forums.

Also,global moderator is another word for super moderator.

You can set their permissions:

ACP=>General Tab=>Forums=>Categories and forums=>Click a forum=>Permissions=>You'll see the global moderator's group,and you can make everyone in that group be able to moderate your selected forums.