adjective

relating to heaven or the sky.

the empyrean domain where human will and God’s will became as one

heavenly,celestial,ethereal,aerial,upper,empyreal

noun

the highest part of heaven, thought by the ancients to be the realm of pure fire.

the unapproachable splendour of the empyrean

heaven,the heavens,the sky,the upper regions,the upper atmosphere,the stratosphere,the ether,the azure,the blue,the wide blue yonder,the firmament,the sphere,the vault (of heaven),the welkin