I might be mistaken, and if I'm wrong I will correct myself. But, I believe the term can go either way. Because I'm thinking there was a semi-pro league in the 1940's that was the "Busch League." And, over the years the term has turned to Bush. So, I'm thinking either term.
Non the less, I feel like I wrote my posts with a joking tone. And, if I offended you I'm not sorry. I'm sorry can't handle jokes.
I do firmly believe the only way to work on a catchers pop is with a fungo and a flip. That way your players can see backspin.