What, exactly, is the occult? Coming from the Latin term occultus, or hidden, occult often refers to hidden or secret knowledge. A synonymous term is esoteric, or "belonging to an inner circle." 
In the context of religion, occultism (or esotericism) signifies non-mainstream, Western mystical and magical traditions, the bulk of which emerges around the 19th and 20th centuries. Wouter Hanegraaff in 2013 explained that "'Western esotericism' is a modern scholarly construct, not an autonomous tradition that already existed out there and merely needed to be discovered by historians."
Inasmuch as "occultism" is an artificial category, this wiki will attempt to cover currents, ideas, and organizations that are distinctly Western in origin, contemplative, sometimes initiatory, and sometimes explore ritual magic approaches.