1911 Encyclopædia Britannica/Aura

AURA (from the Gr. for “breath” or “breeze”), a term used in old days to denote a supposed ethereal emanation from a volatile substance; applied later to the “electrical aura,” or air-current caused by electrical discharge; in epilepsy (q.v.) to one of its premonitory symptoms; and in spiritualism to a mysterious light associated with the presence of spirit-forms. See also Aureola.