Once again, thanks! All bookmarked. I have to admit, after seeing some other threads, I was worried asking what an acronym stands for was sure to illicit nothing but adolescent quips, but I am thankful to get a real answer. Much obliged, folks!
This is probably a really dumb question, but I cannot find it explained anywhere. It is clearly some kind of rating or measurement system, but beyond that it is a mystery to me...any help would be appreciated.