(With apologies to Interconnected for the title format.)
I found out from a chain of comments on the venerable Language Hat that the Jewish surnames Katz, Matz, and Schatz were all originally acronyms.
Katz comes from כוהן צדק kohen tsedek “righteous priest” — you’ll of course recognise kohen as the origin of the surname Cohen, denoting Judaism’s paternal priestly lineage.1
Matz is similarly derived from מורה צדק more tsedek, meaning “teacher of righteousness”, and Schatz, the odd one out, comes from שליח ציבור shaliaẖ tsibur, referring to a cantor, though more literally translated as “emissary of the congregation”.
Meanwhile, in the Russian Empire, bastard children would often have their surnames symbolically clipped just so noöne went around thinking they had anything to do with their aristocratic fathers. Thus Ivan Pnin was the son of Nikolaj Repnin, and Elizabeta Tëmkina was the daughter of Grigorij Potëmkin.
This isn’t a surname, but by all accounts it isn’t a given name either, and once you’ve noticed it, you’ll never be able to unsee it. The name Jebediah does not exist. Jedediah was a very real Biblical figure after whom many a son has been named, but there’s no variant of any real-life person being named Jebediah with a B. (I know what you’re thinking — but, nope, Jeb Bush’s name is… an acronym, again, for John Ellis Bush.)
There’s this weird inconsistency in English in how we treat the names of people from cultures where the surname comes first. Chinese and Korean people usually keep the original order: Qian Xuesen and Bong Joon-ho are indeed from the families Qian and Bong, and it would be quite the faux pas to refer to “Mr Joon-ho”.
Japanese names are less consistent — traditionally they’ve been flipped to conform to the English order, so Hayao Miyazaki was born to a Mr and Mrs Miyazaki, but the trend in recent times has been to restore them to the original order, such that the former foreign secretary officially styles himself as Kōno Tarō, born to Kōno Yōhei.
Then, at the bottom of the ladder, there sits Hungary, whose names are so European-sounding and so universally reordered that most people don’t even realise that, in his home country, the prime minister is called Orbán Viktor. (This gets even more confusing with middle names — the mayor of Budapest, known elsewhere as Gergely Szilveszter Karácsony, is natively Karácsony Gergely Szilveszter, his given name nestled squarely in the middle!)
One last onomastic oddity. In olden days, the capital letter F was written as if double struck, looking like two lowercase f’s put side-by-side. This was copied and copied and misread over and over again until it became the case that some particularly snooty English surnames were properly spelt to begin in lowercase — such as in the cases of Gonville ffrench-Beytagh and Charles ffoulkes. Truly, the irregularities of our language’s orthography know no bounds.