Informally or generally, a mafia is any of various criminal organizations that include, or bear a strong similarity to, the original Sicilian Mafia, the Italian-American Mafia, or other Italian organized crime groups. The central activity of such an organization would be the arbitration of disputes between criminals, as well as the organization and enforcement of illicit agreements between criminals through violence. Mafias often engage in secondary activities such as gambling, loan sharking, drug trafficking, prostitution, and fraud.
The term Mafia was originally applied to the Sicilian Mafia. Since then, the term has expanded to encompass other organizations of similar practices and objectives, e.g. "the Russian mafia" or "the Japanese mafia". The term was coined by the press and is informal; the criminal organizations themselves have their own names (e.g. the Sicilian Mafia and the related Italian-American mafia refer to their organizations as "Cosa nostra"; the "Japanese mafia" calls itself Ninkyō dantai but is more commonly known as "Yakuza" by the public; and "Russian mafia" groups often call themselves "Bratva").