Douglas Harper's Etymology Dictionary
1963, "the Mafia in America," from Italian, literally "this thing of ours."
Usage examples of "cosa nostra".
The Mafia and the Cosa Nostra are one and the same, the whole world knows it, and you're up to your eyes in it, and I know who you are and what you are.
The patriarchs, of whom Maxie Neville was one, examined new candidates for the club with extreme care and ran their specialty with the autocracy of Cosa Nostra chieftans.
On the other hand, I don't believe Gay Rights are very high on the Cosa Nostra's agenda, do you?
Reilly was an OC-Organized Crime-expert who'd spent fifteen busy years attacking the Five Families of the New York Mafia, more often called LCN by the FBI, for La Cosa Nostra.
Yet the FBI director, Hoover, swore there was no such thing as La Cosa Nostra.
The first was the capacity for immediate and massive violence the Russian mafia demonstrated if it was frustrated in any way, a violence that would have made the American Cosa Nostra look positively squeamish.