UNRISD: United Nations Research Institute for Social Development
UNRWA: United Nations Relief and Works Agency for Palestine Refugees in the Near East
UNSC: United Nations Security Council
UNSSC: Untied Nations System Staff College
UNTSO: United Nations Truce Supervision Organization
UNU: United Nations University
UNWTO: World Tourism Organization
UPU: Universal Postal Union
US: United States
USSR: Union of Soviet Socialist Republics (Soviet Union); used for information dated before 25 December 1991