Organized crime is a category of transnational, national, or local groupings of highly centralized enterprises run by criminals to engage in illegal activity, most commonly for profit. Some criminal organizations, such as terrorist groups, are politically motivated. Sometimes criminal organizations force people to do business with them, such as when a gang extorts money from shopkeepers for "protection". Gangs may often be deemed organized crime groups or, under stricter definitions of organized crime, may become disciplined enough to be considered organized. A criminal organization or gang can also be referred to as a mafia, mob, ring, or syndicate; the network, subculture, and community of criminals may be referred to as the underworld. Sociologists define a “mafia” as a type of organized crime group that specializes in the supply of extra-legal protection and quasi-law enforcement. Work on the original “Mafia”, the Sicilian Mafia, which predates the other groups, generated an economic study of organized crime groups and exerted great influence on studies of the Russian mafia, the Chinese triads, Hong Kong mafia, and the Japanese yakuza.
