Temple of Ranma's Sailor Senshi Seifuku

I usually see this in studio apartments, where there's a room containing two floors worth of space and only a portion of the upper half is accessible, often serving as a bedroom. But, when I think "second floor," or "bedroom," that typically brings to mind a floor/ceiling separating two spaces completely, or having four walls and a doorway, respectively. So, is there a term that specifies the kind of area I'm referring to, or does it require a phrase to get the idea cross? I thought it might have been "loft," but the definition and explanation for that doesn't seem to match.

A loft?

So, that's really it? Both Wikipedia and the dictionary I use weren't being clear, talking about attic space, entire rooms being a loft, or there being lofts within lofts... with that last one being accompanied by words like "confusing" and "sometimes," which makes me want to find a better way of referring to it. Aside from "upper open loft area," which is a bit of a train wreck.

Maybe I should make up my own word for it. Something inspired by hayloft, which is short, apt and doesn't leave any room for ambiguity, like using loft could create: "Go to the loft? I thought that's where we were?"

Sounds like a mezzanine level to me.

Hmmmm... I've heard that used for the theater before, but never residential. Would Twilight Sparkle's living space in the library apply?

Architecturally yes, but it wouldn't actually describe the space itself. Its not "the mezzanine" but more (for example) "an open plan bedroom on a mezzanine level" sort of thing.

Another mouthful... I'm thinking of calling it a bedloft. XD

Eh, I live in a apartment like that mine was advertised as a loft apartment.