empyrean
Empyrean (noun) means the highest heaven, supposed by the ancients to be a region of pure light and fire or else composed of ether, and sometimes seen as the dwelling-place of God or other divine beings; the highest celestial sphere according to ancient and medieval astronomy.
Etymology
Derives from Latin empȳreus, itself from Ancient Greek ἐμπύριος (empúrios), which combines ἐν (en, "in") and πῦρ (pûr, "fire") (whence English pyre).