A secret society which organized in Sicily as a political organization, but is now widespread among Italians, and is used to further or protect private interests, reputedly by illegal methods; called also the Sicilian Mafia.
A group of loosely associated of criminal organizations in the United States, some having ties to the Sicilian Mafia, and organized in "families"; the term is applied to the entire group of organizations, or to any one local group. Also, loosely, organized groups of criminals anywhere, as the Russian mafia.
Any tightly knit group of trusted associates having strong control or influence in some area; as, Kennedy and his Irish Mafia. (informal)