archaic the highest part of the (supposedly spherical) heavens, thought in ancient times to contain the pure element of fire and by early Christians to be the abode of God and the angels
2.
poetic the heavens or sky
—adj
3.
of or relating to the sky, the heavens, or the empyrean
4.
heavenly or sublime
5.
archaic composed of fire
[C17: from Medieval Latin empyreus, from Greek empuros fiery, from pur fire]
mid-14c. (as empyre), from Gk. empyros "fiery," from pyr "fire;" confused by early writers with imperial. In Gk. cosmology, the highest heaven, the sphere of pure fire; later baptized with a Christian gloss as "the abode of God and the angels."