Why We Say: X-Y-Z

It’s here. We’ve reached the end of the book, Dictionary of Word Origins: A History of the Words, Expressions, and Clichés We Use by Jordan Almond. Let’s finish this out.
X-Ray: It’s called an “X-Ray” because the scientist, by the name of Roentgen, preferred it. We could be calling it the “Roentgen ray” but he had the better idea. He used “X” because it symbolizes the unknown and Roentgen did not understand how his discovery worked.
Yankee: Can you imagine calling the New York Yankees the New York Cheeses? Who wants to root for a cheesy team? Yankee is a Dutch nickname “Jan Kass,” which means “John Cheese.” Besides tulips, Holland is known for its cheeses so calling someone a “Yankee” makes sense, right? Not yet? Let’s go further. Back in the time of pirates, English sailors called Dutch pirates “Yankees.” It wasn’t a compliment. They were probably called them cheeseheads–definitely insulting. When the Dutch settled in New York, for some reason, began calling the English settlers of Connecticut “Yankee.” It came to be a term referring to dislike, especially to those in colonies further North. What does this do with baseball teams? Not sure, but I’m open to suggestions.
Zany: A type of Italian play, Comedia dell’ arte, consisting of comic performance was referred to as zani. This transfers to clowning around or being “zany.”
Why We Say: X-Y-Z. I occasionally search meaning of words.
I had never read that before about zany!
Some of the original background info is surprising!
Definitely!!!