*UPDATE* – Thanks to yupdiduda for their contribution! It seems as though this word is used in a metaphorical and perhaps tongue-in-cheek sense, rather than being something used as purely a synonym. See this website as an example of how it is used…
Noun. From German.
“A room designed specifically for exercise; a gym room”
You might be thinking, “Hold on, this isn’t as weird as I was expecting, considering your other posts.”
I guess that’s true. However, if you speak German, you’ll see that the literal translation is something a little more sinister; specifically, Folterkammer translates as torture chamber. A Google Image search produces imagery of both descriptions (disclaimer: I warn you that some of the pictures may be a little graphic and I take no responsibility for any long-term damage that may ensue!) but it seems as though the Germans have this one in the bag.
Who’d be silly enough to go to a gym, let alone have a dedicated room in your house as a gym?! =P