Lat. In Roman law. In ancient times the nerum seems to have been a species of formal contract, involving a loan of money, and attended with peculiar consequences, solemnized with the “copper and balance.” Later, it appears to have been used as a general term for any contract struck with those ceremonies, and hence to have included the special form of conveyance called “mancipatio.” In a general sense it means the obligation or bond between contracting parties. See Maine, Anc. Law, 305, ét seg.; Hadl. Rom. Law, 247.