Today’s word is my only friend, the end. Or any writer’s
only friend, really.

End comes from the Old English ende, which bizarrely enough meant end.
Before that, it was the Proto Germanic andja, which originally meant the
opposite side, and even further back in Proto Indo European it’s antjo, which means end, but more
in a boundary sense. In Proto Indo European, the word ant means before or opposite, and it’s where we get ante from.
Originally, end just meant the limits of something, like the ends of the Earth
(the only way it’s still used according to its original meaning).
So let this be a lesson to you: a person isn ’t using a word wrong. They’re ahead of their time.
Sources
Tony Jebson’s page on the Origins of Old English