However, the periodic symbol for gold is uppercase A and lowercase u. The acronym for about uncirculated is uppercase A and U.
Which is why I wrote it "Au" not "AU" although you cannot be certain that we will always find it employed correctly in common usage if someone types or writes in all caps or casually only in lower case, as many are becoming accustomed to doing online or when txting, emailing and such.
I guess I was from the middle. We drank "soda pop". Anywho, here is PCGS's definition. That should be the end all to this discussion. The others are all similarly laid out.
Actually, down south we drink Coke. Whether it be Pepsi, Coca-Cola, RC, Dr. Pepper Co., etc. etc. etc. Oh, and its About Uncirculated