an agreement between two states for the exchange of their prisoners of war.

Cartel signifies also a letter of defiance or a challenge to decide a controversy either in a tournament or in a single combat. See Duel.

CARTEL Ship, a ship commissioned in time of war to exchange the prisoners of any two hostile powers; also to carry any particular request or proposal from one to another; Cartel Ship, another: for this reason the officer who commands her is particularly ordered to carry no cargo, ammunition, or implements of war, except a single gun for the purpose of firing signals.