I was reading some Spanish grammar stuff, and it mentioned the word "cuyo" as basically meaning "whose". I've literally never heard of this word before, and I've studied Spanish since middle school and even spoken it with people conversationally, so I'm very confused.
It seems like this would be a really common word, but I swear I've never encountered it before. Is it regional, or rarely used, or have I just managed to overlook it for years?
I instinctively understand it as related to mío and tuyo, and usually connected to a subordinate clause. Like a mix of "su-io" and "qué-io".
It might be descended from "quam" in Latin, idk.