Me being me, though, I'm mostly still hung up on the word "rook."*1 It came along about the time that English was Middle English, by way of Old French roc. But it was ultimately from Persian rukh, according to the Oxford Universal Dictionary. The OUD demurely does not define rukh, but the online consensus seems to be that it's related to the Hindi word for chariot: rath. *2 The prevailing view being that chess originated in northern India, or thereabouts, this origin of the word seems a reasonable assumption, even if it would be more satisfying to know more about the phonology that resulted in the Persian form. (The Online Etymological Dictionary has a succinct entry on rook.)
I find it entirely fascinating that rukh made its way over thousands of miles with so little change. Especially, since the imagined character of the piece did change. The Persian fil, elephant, became, as I mentioned, our bishop; our queen retains neither linguistic nor symbolic trace of the Persian vazir. But if the rukh settled down and became a castle, it kept its name all the same.
*1 Not to be confused with "rook" as a type of bird. That one came from Old English hroc. Which, in turn, shouldn't be confused with that bird from the Arabian Nights, the roc, a name which quite inconveniently, we possibly got from Arabic rokh. . .or Persian rukh. The latter which, I assume, isn't the same kind of Persian rukh as the chess piece, but language is a weird thing, so who's to say?
*2 Straying from the chessboard entirely, but I suspect to most English speakers (speaking from English speaking experience) that rather looks as though it should be pronounced rather like, "wroth." In this case, it's actually closer to "rut," with a rather explosive "t," if that might assist the linguistic musings. . .