cartel

noun

1. A group of businesses or nations that collude to limit competition within an industry or market.

   “oil cartel”

   “drug cartel”

   “Over the past decade, the very nature of organized crime has changed, with many groups diversifying their income beyond drug trafficking, and large cartels splintering into smaller, oftentimes more nimble groups.”

2. (historical)A combination of political groups (notably parties) for common action.
3. (historical)A written letter of defiance or challenge.

   “He is cowed at the very idea of a cartel.”

   “Xerxes whipped the Sea, and writ a cartell of defiance to the hill Athos.”

4. (historical)An official agreement concerning the exchange of prisoners.

   “He then sent down a flag of truce in military style, proposing a cartel or exchange of prisoners – the corporal for the notary.”

5. (historical)A ship used to negotiate with an enemy in time of war, and to exchange prisoners.