Any of various oath-bound societies devoted to brotherhood (or sisterhood), moral discipline, and mutual assistance.
Such societies usually conduct rituals of initiation to instruct new members in the rules of the group (see rite of passage ). Greek and Roman mystery religion s had their secular counterparts in clandestine social clubs, some of which served as platforms for political dissent. In West Africa secret societies such as Poro (for men) and Sande (for women) serve to translate slight advantages of wealth and prestige into political authority. In parts of New Guinea secret men's societies serve as repositories of tribal knowledge. Fraternal orders such as the Freemasons (see Freemasonry ) may be considered secret societies, as may criminal groups such as the Mafia and the Chinese Triad s and hate groups such as the Ku Klux Klan .