Name for a kingdom that only exists in mirrors?

I'm embarking on a new worldbuilding project. This new world will be inspired by French folkore and fairy tales and will likely be the setting of a few tales.

I need a name for a kingdom that only exists in the reflections of mirrors. The only thing that I can come up with is Lune, or Ys (lost city off the coast of Brittney; the tale is what started my love of folklore).

Any guidence would be appreciated.