Today’s word is keep because it’s the first word I could think of that started with K.
Keep comes from the Old English word cepan, which meant seize, hold…or observe. Hm. Anyway, before that, it was the Proto Germanic kopijan and then, while there are a few maybes, there’s nothing for sure. That observe definition means it might be related to the Old English capian, to look, and from observe we got “keep an eye on” and then just keep. It’s an interesting theory, for sure, and certainly crazy enough to be true!
Tony Jebson’s page on the Origins of Old English