When referring to countries, use the terms developing countries and developed countries, or low-, middle- and high-income countries. Do not use underdeveloped countries or terms that should have a geographical meaning only, such as the West, westernised, north or south.

The term Third World was coined for developing countries because they are typically in Asia, Africa, Latin America and the Pacific, and therefore independent of either the western or eastern blocs. This term, and the corresponding First World, are best avoided because they are judgmental and not internationally accepted.