So a furnace and an oven are the same thing?
Yes. But furnace can have other specific meanings that are added after the word forno
When I peeked, it gave me "a fornalha" for furnace.. But I accidentally typed "o fornalha" and it showed the "correct solutions" as "o forno" and "a fornalha".
got the same, there's a problem here: the hints say: "o fornalha"; I typed "o fornalha" and got dinged saying that fornalha is feminine. Does this qualify fornalha as neuter gender :-)?