Noah Webster
Empyreal
EMPYR'EAL, adjective [Latin empyroeus; from Gr. fire.]
1. Formed of pure fire or light; refined beyond aerial substance; pertaining to the highest and purest region of heaven.
Go, soar with Plato to the empyreal sphere.
2. Pure; vital; dephlogisticated; an epithet given to the air, or rather gas, now called oxygen.