The occult (from the Latin word occultus "clandestine, hidden, secret") is "knowledge of the hidden". In common English usage, occult refers to "knowledge of the paranormal", as opposed to "knowledge of the measurable", usually referred to as science. The term is sometimes taken to mean knowledge that "is meant only for certain people" or that "must be kept hidden", but for most practicing occultists it is simply the study of a deeper spiritual reality that extends beyond pure reason and the physical sciences. The terms esoteric and arcane can also be used to describe the occult, in addition to their meanings unrelated to the supernatural.
It also describes a number of magical organizations or orders, the teachings and practices taught by them, and to a large body of current and historical literature and spiritual philosophy related to this subject.
Occultism is the study of occult practices, including (but not limited to) magic, alchemy, extra-sensory perception, astrology, spiritualism, religion, and divination. Interpretation of occultism and its concepts can be found in the belief structures of philosophies and religions such as Chaos magic, Gnosticism, Hermeticism, Theosophy, Wicca, Thelema and modern paganism. A broad definition is offered by Nicholas Goodrick-Clarke: