multilateral

Since lateral means "side", multilateral means basically "many-sided". The philosophy of multilateralism claims that the best solutions generally result when as many of the world's nations as possible are involved in discussions, and multilateralists often favor strengthening the United Nations. Today multilateralism can be seen at work in, for example, the World Health Organization, the World Trade Organization, and the International Criminal Court. But the U.S. doesn't always join the major multilateral organizations, instead often behaving as if a unilateral approach—that is, going it alone—was best for the interests of a powerful nation.