There's also Ulysses S. Grant. The "S" was apparently just a mistake on his enrollment at West Point. His birth name was Hiram Ulysses Grant. He tried to switch his first and middle names, but ended up with the initials USG instead of UHG.
And then there's the odd case of "Thomas a Becket." Thomas Beket was never called Thomas a Becket in his lifetime. He apparently went by many names, one of which was "Beket," but never "a Becket."
I have a family member whose middle name is a letter. A friend of mine has two family members that only have initials for their first name (one was named for the other). When the older joined the army they just gave him a name that fit the initials and that went on all his official paperwork.
I had a friend like this in college. His name was AJ. That's it. Just the letters.
Everyone in the department spent ages trying to guess what it stood for. I managed to glance his ID when we got lunch together once. His name was just AJ. There weren't even periods marking it as an abbreviation.
Have an old friend/colleague with the last name Oh, share the same first name, so at work we would always say, John S., John D, John O type of deal, for some reaosn it would keep me wondering if we were really saying Oh or O. For him. (John isn't really the first name, just an example)
I used to work with a guy that was from China. He only had a first in a last name. He was going to college here and the college required everyone to have a middle initial as part of their login. They just used his last initial as his middle initial.
Wait does everyone there have a middle name? I'm Dutch and I don't have a middle name. I figured that was quite common also in the English speaking world
He's the only person I've known here in almost 50 years without a middle name. It's quite possible other people haven't had a middle name but it's never come up.
To be fair to the person above, that's actually the source given for how Truman wrote his own name, not for the S not standing for anything. The reference for that is number 8, which is a book rather than a website. That said, the one you linked does back up the S not standing for anything anyway
What a coincidence. I never knew this despite my penchant for useless trivia but just yesterday at an airport I overheard some high school kids asking each other trivial pursuit questions and this was one. The next day: this post. Uncanny.