“Defenestration” was also the best slang for quitting Windows, back in the day.
When are where was that? I've never heard that usage
I remember it verbally in the mid-2000s.
Heh, sorry to disagree, but that's a big nope. I learned the word in my teens, back in the 70s, from the Arthur C. Clarke story "The Defenestration of Ermintrude Inch" in his "Tales from the White Hart" collection of SF-oriented tall tales.
TIL that "Tales from the White Hart" had at least some readership in the USA - I would have feared that its air of post-war English constraints (rationing and London grime) felt almost more fantastical than the accounts of Harry Purvis.
As an avid SF reader back then, I pretty much devoured everything by the big 3 of Clarke, Asimov, and Heinlein. And lots of others, of course - the Callahan's Bar shorts by Spider Robinson were a fun update of the Tales from the White Hart idea.
I learned the word from the band REM, specifically lyricist Michael Stipe commenting that their 1991 song, Belong was NOT a song about defenestration.