Empyreal \Em*pyr"e*al\, a. [L. empyrius, empyreus, fiery, Gr. ?, ?, in fire, fiery; ? in + ? fire. See {In}, and {Fire}.] Formed of pure fire or light; refined beyond a["e]rial substance; pertaining to the highest and purest region of heaven. Go, soar with Plato to the empyreal sphere. --Pope. {Empyreal air}, oxygen gas.