Tolkien's "Middle-Earth" is itself a "folksy mistranslation"
Closer translation-- "Middle-Yard"
Old English word eardgeard =Earth-Yard
/ ˈæ͜ɑrdˌjæ͜ɑrd / "ardyard" /
https://www.theundergroundmap.com/article.html?id=104937
https://english.nsms.ox.ac.uk/oecoursepack/wanderer/notes/no...
I went straight to metric and Middle Metre approximate and is wrong.