A secret society is a group or organization that operates in secrecy, keeping its activities, rituals, and membership confidential. These societies often have unique traditions, oaths, and initiation ceremonies that members must undergo to join. The purpose and objectives of secret societies can vary widely, from social and fraternal organizations to groups with political, religious, or intellectual goals. Common characteristics of secret societies include selective membership, a structured hierarchy, and the use of symbols and codes to communicate and identify members. Notable examples of secret societies include the Freemasons, Skull and Bones, and the Rosicrucians.