"Gueroult: I thought that conceivably Midgard might be Middle-earth or have some connection? Tolkien: Oh, it is; they're the same word. Most people have made this mistake of thinking Middle-earth is a particular kind of Earth or is another planet of the science-fiction sort, but it's simply an old-fashioned word for this world we live in, as imagined surrounded by the ocean. Gueroult: It seemed to me that Middle-earth was, in a sense, as you say, "this world we live in", but this world we live in at a different era. Tolkien: No, at a different stage of imagination, yes."