{ ‖‖, n. [ It. maffia. ] 1. 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. [ wns=2 ] [ Webster 1913 Suppl. ]

2. 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. [ wns=1 ]
Syn. -- syndicate, mob, Cosa Nostra, La Cosa Nostra, organized crime. [ WordNet 1.6 + PJC ]

3. Any tightly knit group of trusted associates having strong control or influence in some area; as, Kennedy and his Irish Mafia. [ informal ] [ wns=3 ] [ PJC ]