Quiz: Remember the definition of mal de mer?
1550s, "a written challenge," from Middle French cartel (16c.), from Italian cartello "placard," diminutive of carta "card" (see card (n.1)). It came to mean "written agreement between challengers" (1690s) and then "a written agreement between challengers" (1889). Sense of "a commercial trust, an association of industrialists" comes 1902, via German Kartell, which is from French. The older U.S. term for that is trust (n.). The usual German name for them was Interessengemeinschaft, abbreviated IG.