It originated in Prague due to two incidents:

* https://en.wikipedia.org/wiki/Defenestration#Origin

* https://en.wikipedia.org/wiki/Defenestrations_of_Prague

Not at all. It's just the Latin prefix "de" (out of) plus "fenester" meaning window. Not an English word except by borrowing.

Is it? I know of that word in at least 3 languages.