Cosa Nostra is a criminal society and organization operating on the island of Sicily since the 19th century. It is a coalition of gangs that sell their protection and is made up of about one hundred groups known as "families," "cosche," "borgatas," or "clans". Each of these claims sovereignty over a territory, usually a town or village or a neighborhood of a larger city, though without ever fully conquering and legitimizing its. The term Cosa Nostra means "our thing" in English and was coined by Sicilians to represent the Sicilian Mafia. The Sicilian Mafia is not a centralized organization but rather a loose confederation. It should not be confused with other mafia-type organizations in Southern Italy, such as the Ndrangheta in Calabria, the Camorra in Campania, or the Sacra Corona Unita and Società foggiana in Apulia.

The Sicilian Mafia is hierarchically structured and is led by a boss (or don) who is elected by his fellow members (mafiosi) for a one-year term. He runs the clan with the assistance of a lieutenant called an underboss (capo bastone or sotto capo). The boss also has a counselor (consigliere), who is elected to provide a neutral perspective on the clan’s activities, as well as to keep an eye on the leadership.

Cosa Nostra has been involved in a broad spectrum of illegal activities, including extortion, corruption of public officials, gambling, infiltration of legitimate businesses, labor racketeering, loan sharking, and more. They have also carried out multimillion-dollar frauds in health insurance, prepaid telephone cards, and victimizing small Wall Street brokerage houses. The Sicilian Mafia has diversified its activities and extended its penetration in legal markets by switching to white-collar crimes in recent years.

In conclusion, Cosa Nostra is a criminal society and organization operating on the island of Sicily since the 19th century. It is a coalition of gangs that sell their protection and is made up of about one hundred groups known as "families." The Sicilian Mafia is hierarchically structured and is led by a boss who is elected by his fellow members. They have been involved in a broad spectrum of illegal activities, including extortion, corruption of public officials, gambling, infiltration of legitimate businesses, labor racketeering, loan sharking, and more.