NATIONS UNITED' Nations United is a term used to describe countries that have formed an alliance or partnership. This term is often used to refer to the United Nations, an international organization founded in 1945 with the aim of maintaining world peace and security. The term can also be used to refer to any group of countries that have joined forces for a common purpose. The word 'allies' is often used to describe such a group, as it implies a strong bond between the countries involved.