The aether was believed to be the substance which filled the region of the universe above the terrestrial sphere. Aristotle included it as a fifth element distinct from the other four, Earth, Water, Air, and Fire. Aether was also called Quintessence (from quinta essentia, "fifth element"). Its Platonic solid, according to Plato, was the Dodecahedron.
The word aether (αἰθήρ) in Homeric Greek means "pure, fresh air" or "clear sky", imagined in Greek mythology to be the pure essence where the gods lived and which they breathed, analogous to the aer breathed by mortals (also personified as a deity, Aether, the son of Erebus and Nyx). It corresponds to the concept of akasha in Hindu philosophy. It is related to αἴθω "to incinerate", also intransitive "to burn, to shine" (related is the name Aithiopes (Ethiopians), meaning "people with a burnt (black) visage". See also Empyrean.Aristotle added aether to the system of the classical elements of Ionic philosophy as the "fifth element" (the quintessence), on the principle that the four terrestrial elements were subject to change and moved naturally in straight lines while no change had been observed in the celestial regions and the heavenly bodies moved in circles. In Aristotle's system aether had no qualities (was neither hot, cold, wet, nor dry), was incapable of change (with the exception of change of place), and by its nature moved in circles. Medieval scholastic philosophers granted aether changes of density, in which the bodies of the planets were considered to be denser than the medium which filled the rest of the universe. Robert Fludd stated that the aether was of the character that it was "subtler than light". Fludd cites the 3rd century view of Plotinus, concerning the aether as penetrative and non-material.
In Wicca, it is the unifying energy inherent in every living creature on the planet, and in all four elements (earth, air, water, and fire) in nature: [[ Essentially it is spirit: and soul, the all-encompassing spirit energy of the Goddess and God. On the pentagram, akasha is assigned to the fifth top point, and the "other" element