The occult is a category of supernatural beliefs and practices, encompassing such phenomena as those involving mysticism, spirituality, and magic in terms of any otherworldly agency. It can also refer to other non-religious supernatural ideas like extra-sensory perception and parapsychology. The occult (from the Latin word occultus "clandestine, hidden, secret") is "knowledge of the hidden". In common 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. The term occult sciences was used in the 16th century to refer to astrology, alchemy, and natural magic, which today are considered pseudosciences. The term occultism emerged in 19th-century France, where it came to be associated with various French esoteric groups connected to Éliphas Lévi and Papus, and in 1875 was introduced into the English language by the esotericist Helena Blavatsky. Throughout the 20th century, the term was used idiosyncratically by a range of different authors, but by the 21st century was commonly employed – including by academic scholars of esotericism – to refer to a range of esoteric currents that developed in the mid-19th century and their descendants. Occultism is thus often used to categorise such esoteric traditions as Spiritualism, Theosophy, Anthroposophy, the Hermetic Order of the Golden Dawn, and New Age. 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. (en)