Yes, POTUS is President of the United States. And SCOTUS is the Supreme Court of the United States. It's media/PR shorthand.
There was one on the Late Late recently from that guy from Game For A Laugh (a popular ITV show in the 70s, apparently). He didn't give the answer AFAIK -
If One, Five and Six had the same name, what did Three Call her sixth?
Or something like that? Anyone catch it or figure it out? I think I know what it's about but not sure if I heard the second part properly...