The Human Aura Astral Colors and Thought Forms - William Walker Atkinson - Bog

The above question is frequently asked the student of occultism by some one who has heard the term but who is unfamiliar with its meaning. Simple as the question may seem, it is by no means easy to answer it, plainly and clearly in a few words, unless the hearer already has a general acquaintance with the subject of occult science. Let us commence at the beginning, and consider the question from the point of view of the person who has just heard the term for the first time.
The dictionaries define the word aura as: "Any subtle, invisible emanation or exhalation." The English authorities, as a rule, attribute the origin of the word to a Latin term meaning "air," but the Hindu authorities insist that it had its origin in the Sanscrit root Ar, meaning the spoke of a wheel, the significance being perceived when we remember the fact that the human aura radiates from the body of the individual in a manner similar to the radiation of the spokes of a wheel from the hub thereof. The Sanscrit origin of the term is the one preferred by occultists, although it will be seen that the idea of an aerial emanation, indicated by the Latin root, is not foreign to the real significance of the term...