treaty
trea.ty \'tre-t-e-\ n [ME tretee, fr. MF traite`, fr. ML tractatus, fr. L handling], treatment, fr. tractatus, pp. of tractare to treat 1: the action of treating and esp. of negotiating 2a: an agreement or arrangement made by negotiation : 2a1: PRIVATE TREATY 2a2: a contract in writing between two or more political authorities (as st ates or sovereigns) formally signed by representatives duly authorized and usu. ratified by the lawmaking authority of the state 2b: a document in which such a contract is set down
Webster's English Dictionary