Table of contents
1 Physics and philosophy
2 Greek mythology
3 Magick

Physics and philosophy

In physics and philosophy, aether (also spelt ether) was once believed to be a substance which filled all of space. Aristotle included it as a fifth element on the principle that nature abhorred a vacuum. Aether was also called "Quintessence."

See also luminiferous aether for the late 19th century invocation of this concept by physicists as an attempt to reconcile electromagnetic theory and Newtonian physics.

This meaning of a signal-carrying medium is the origin of the name Ethernet.

Greek mythology

Aether ("upper air"), in Greek mythology, was the personification of the "upper sky", space and heaven. He is the pure, upper air that the gods breathe, as opposed to "aer", which mortals breathed. He was the son of Erebus and Nyx, and brother of Hemera. He is the soul of the world and all life emanates from him.

Magick

In magick, it is called the fifth element or quintessence, also called akasha, sacred sound, or spirit.