If you re-read the quoted bit it addresses this "dark side" vs "far side": > The hemisphere is sometimes called the "dark side of the Moon", where "dark" means

If you re-read the quoted bit it addresses this "dark side" vs "far side": > The hemisphere is sometimes called the "dark side of the Moon", where "dark" means "unknown" instead of "lacking sunlight" [ed note: compare "dark ages"] So the "unknown" (relatively anyway) side of the moon is less mapped, but not because it's unlit, but because it's dark. The lit side of the moon is well mapped, not because it's always lit - sometimes it's unlit, but it's certainly the known bit as we've been looking at it since before we were human.