U
UAE United Arab Emirates
UDEAC Union Douaniere et Economique de l'Afrique Centrale; see Central African Customs and Economic Union (UDEAC)
UEMOA Union Economique et Monetaire Ouest Africaine; see West African Economic and Monetary Union (WAEMU)
UHF ultra-high-frequency
UK United Kingdom
UN United Nations
UNAMIR United Nations Assistance Mission for Rwanda
UNAMSIL United Nations Mission in Sierra Leone
UNAVEM III United Nations Angola Verification Mission III