The literal meaning of Italian cartello, a derivative of carta, “leaf of paper,” is “placard.” The word is also used for a letter of defiance or a challenge. In this sense the Italian word was borrowed into Middle French as cartel, and the French word was borrowed into English. In English, a cartel was originally a letter of defiance. Later the word came to be used for a written agreement between warring nations to regulate such matters as the treatment and exchange of prisoners. Another type of agreement, a combination of commercial enterprises, is now called a cartel.

A cartel is an organization of a few independent producers for the purpose of improving the profitability of the firms involved. This usually involves some restriction of output, control of price, and allocation of market shares. Members of a cartel generally maintain their separate identities and financial independence while engaging in cooperative policies. Cartels can either be domestic or international. Because cartels restrict competition and result in higher prices for consumers, they are outlawed in some countries. The only industry operating in the U.S. with a blanket exemption from the antitrust laws is major-league baseball.