Late :) but sithis is the space between celestial bodies

Thanks for bringing this up, I removed the word since as you mentioned it wouldn't fit in the Elder Scrolls cosmology. That leaves a word for physical space still open.

Isn't Sithis considered to be the Void of empty space between celestial bodies? Considering dragons seem rather knowledgeable about more or less everything, I'd find it odd if they didn't have their own variant. Still, "Sithis" is in and of itself enough, in my opinion.