I have heard that a RACK is a portion of, usually half of, a full SLAB.
Bear in mind, I may have no idea what I am talking about. I DO know I have a few slabs cooking right now.
(And this brings up a topic I was thinking about today. Does anybody pre cut their slabs in to 3-4 rib portions BEFOR cooking? It seems they might cook slightly quicker, but there are lots of reasons to do this, especially if serving folks 'hot off the grill or in vendoing scenarios. Thoughts?)