La Cosa Nostra is the name by which members of the Mafia in the United States refer to the organization. The term is believed to have been coined by Salvatore Maranzano in the spring of 1931 when he named himself Capo di tutti capi, or "boss of all bosses" of Italian-American organized crime, after his victory over mobsters loyal to Joe Masseria in the Castellammarese War.

The precise translation of the phrase has been the subject of some lively debate; the basic rendering would be "our thing," but according to Joe Valachi, most members themselves preferred to use "this thing of ours" instead when referring to it in English.

The abbreviation LCN is sometimes used by law-enforcement officials, especially those employed by the Federal Bureau of Investigation (in 1970, United States Attorney General John Mitchell ordered that official documents emanating from the Justice Department no longer use the word "Mafia," after the Italian-American Civil Rights League voiced objections to the word's use).