| 項目 |
| U［(ド) Uran］ |
| U 形鋼［U-shaped steel］ |
| U 字管［U-shaped tube］ |
| U 字谷［U-shaped valley; (ド) U-Tal］ |
| U ターン［U-turn］ |
| U ボート［(ド) U-Boot; Unterseeboot］ |
| u［atomic mass unit］ |
| UA1［Ukraine］ |
| UA2［United Airlines］ |
| UAAC［Un-American Activities Committee］ |
| UAE［United Arab Emirates］ |
| U.A.T.I.［(フ) Union des associations techniques internationales］ |
| UAW［United Automobile Workers］ |
| U.B.［under bust］ |
| U-bomb［uranium bomb］ |
| UC［The University of California］ |
| UCB［University of California at Berkeley］ |
| UCC［Universal Copyright Convention］ |
| U.C.I.［(フ) Union cycliste internationale］ |
| UCLA［University of California at Los Angeles］ |
| UCP［Uniform Customs and Practice for Documentary Credits］ |
| UCP500［Uniform Customs and Practice for Documentary Credits（1993 Revision）］ |
| UDA［Ulster Defence Association］ |
| UDC［Universal Decimal Classification］ |
| UDEAC［(フ) Union Douaniere et Economique de l'Afrique Centrale］ |
| U.D.F.［(フ) Union pour la democratie francaise］ |
| U.D.R.［(フ) Union des democrates pour la Republique］ |
| UEA（ウエア）［(エスペラント) Universala Esperanto Asocio］ |
| UEFA（ユーエイファ）［Union of European Football Associations］ |
| UEMOA［(フ) Union Economique et Monetaire Ouest Africaine］ |
| UFO（ユーフォー）［unidentified flying object］ |
| UG1［Republic of Uganda］ |
| UG2［user group］ |
| UGA［Republic of Uganda］ |
| UHF［ultrahigh frequency］ |
| UHT［ultrahigh temperature］ |
| UHV 送電［ultrahigh voltage］ |
| UI［university identity］ |
| U.I.C.C.［(ラ) Unio Internationalis Contra Cancrum］ |
| UICN［Universal and Intelligent Communication Network］ |
| U.I.P.M.［(フ) Union internationale de pentathlon moderne］ |
| U.K.［United Kingdom of Great Britain and Northern Ireland］ |
| UKR［Ukraine］ |
| UL［Air Lanka］ |
| ULCC［ultra large crude carrier］ |
| ULP［ultra-light plane］ |
| ULSI［ultra large-scale integration］ |
| UMNO［United Malays National Organization］ |
| UN［United Nations］ |
| UNA［United Nations Association］ |
| UNAFEI（ユナフェイ）［United Nations Asia and Far East Institute for the Prevention of Crime and the Treatment of Offenders］ |
| UNAMIR［United Nations Assistance Mission for Rwanda］ |
| UNAVEM II［United Nations Angola Verification Mission II］ |
| UNAVEM III［United Nations Angola Verification Mission III］ |
| UNC［United Nations Charter］ |
| UNCD［United Nations Conference on Desertification］ |
| UNCDF［United Nations Capital Development Fund］ |
| UNCED［United Nations Conference on Environment and Development］ |
| UNCHS［United Nations Center for Human Settlements］ |
| UNCITRAL［United Nations Commission on International Trade Law］ |
| UNCRD［United Nations Center for Regional Development］ |
| UNCRO［United Nations Confidence Restoration Operation］ |
| UNCTAD（アンクタッド）［United Nations Conference on Trade and Development］ |
| UNDC［United Nations Disarmament Commission］ |
| UNDD［United Nations Development Decade］ |
| UNDOF（アンドフ）［United Nations Disengagement Observer Force］ |
| UNDP［United Nations Development Program］ |
| UNDRO（アンドロ）［Office of the United Nations Disaster Relief Coordinator］ |
| UNEF（ユネフ）［United Nations Emergency Forces］ |
| UNEP（ユネップ）［United Nations Environment Program］ |
| UNESCO, Unesco（ユネスコ）［United Nations Educational，Scientific and Cultural Organization］ |
| UNF［United Nations Force］ |
| UNFCCC［United Nations Framework Convention on Climate Change］ |
| UNFDAC［United Nations Fund for Drug Abuse Control］ |
| UNFICYP［United Nations Peace-Keeping Force in Cyprus］ |
| UNFPA［United Nations Population Fund］ |
| UNGA［United Nations General Assembly］ |
| UNHCHR［United Nations High Commissioner for Human Rights］ |
| UNHCR［Office of the United Nations High Commissioner for Refugees］ |
| UNIC［United Nations Information Center］ |
| UNICEF, Unicef（ユニセフ）［United Nations Children's Fund］ |
| UNIDIR（ユニディール）［United Nations Institute for Disarmament Research］ |
| UNIDO（ユニド）［United Nations Industrial Development Organization］ |
| UNIFEM（ユニフェム）［United Nations Development Fund for Women］ |
| UNIFIL（ユニフィル）［United Nations Interim Force in Lebanon］ |
| UNIKOM（ユニコム）［United Nations Iraq-Kuwait Observation Mission］ |
| UNITA［(ポルトガル) Uniao Nacional para Independencia Total de Angola］ |
| UNITAF［United Task Force］ |
| UNITAR［United Nations Institute for Training and Research］ |
| UNIX |
| UNMIH［United Nations Mission in Haiti］ |
| UNMOT［United Nations Mission of Observers in Tadhikistan］ |
| UNO［United Nations Organization］ |
| UNOMA［United Nations Observer Mission in Angola］ |
| UNOMIL［United Nations Observer Mission in Liberia］ |
| UNOMSA［United Nations Observer Mission to South Africa］ |
| UNOSOM［United Nations Operation in Somalia］ |
| UNP［United National Party］ |
| UNPF［United Nations Peace Force］ |
| UNPREDEP［United Nations Preventive Deployment］ |
| UNPROFOR（アンプロフォー）［United Nations Protection Force］ |
| UNRISD［United Nations Research Institute for Social Development］ |
| UNRRA, Unrra（アンラ）［United Nations Relief and Rehabilitation Administration］ |
| UNRWA（アンルワ）［United Nations Relief and Works Agency（for Palestine Refugees in the Near East）］ |
| UNSC［United Nations Security Council］ |
| UNSCOM［United Nations Special Commission］ |
| UNSF［United Nations Stand-by Force］ |
| UNSMA［United Nations Special Mission in Afghanistan］ |
| UNTAC（アンタック）［United Nations Transitional Authority in Cambodia］ |
| UNTC［United Nations Trusteeship Council］ |
| UNTDB［United Nations Trade and Development Board］ |
| UNTMIH［United Nations Transition Mission in Haiti］ |
| UNTSO（アンツォ）［United Nations Truce Supervision Organization］ |
| UNU［United Nations University］ |
| UNV［United Nations Volunteers］ |
| UPI［United Press International］ |
| UPOV（ウポブ，ユポブ）条約［(フ) Union Internationale pour la Protection des Obtentions Vegetales］ |
| UPS［uninterruptible power supply］ |
| UPU［Universal Postal Union］ |
| UR［Uruguay Round］ |
| UrEDAS（ユレダス）［Urgent Earthquake Detection and Alarm System］ |
| URL［uniform resource locator］ |
| URNG［(ス) Unidad Revolucionaria Nacional Guatemalteca］ |
| URSI［(フ) Union radio-scientifique internationale］ |
| URU［Oriental Republic of Uruguay］ |
| US［United States of America］ |
| US スチール［US Steel］ |
| USA1［United States Army］ |
| USA2［United States of America］ |
| USAF［United States Air Force］ |
| USAFA［United States Air Force Academy］ |
| USAID［US Agency for International Development］ |
| USB［universal serial bus］ |
| U.S.C., USC［United States Code］ |
| USCG［United States Coast Guard］ |
| USDA,U.S.D.A.［United States Department of Agriculture］ |
| U.S.G.A.,USGA［United States Golf Association］ |
| USIS［United States Information Service］ |
| USMA［United States Military Academy］ |
| USMC［United States Marine Corps］ |
| USN［United States Navy］ |
| USNA［United States Naval Academy］ |
| USNG［United States National Guard］ |
| USS1［United States Senate］ |
| USS2［United States Steel］ |
| USSR［Union of Soviet Socialist Republics］ |
| USTOL（ユーストール）［ultrashort takeoff and landing aircraft］ |
| USTR［Office of the United States Trade Representative］ |
| USW［ultrashort wave］ |
| USWA［United Steelworkers of America］ |
| USX［USX Corp.］ |
| UT［universal time］ |
| UTC［universal time coordinated］ |
| UTMS［Universal Traffic Management System］ |
| .uu |
| UUCP［UNIX to UNIX copy］ |
| .uue |
| UUS［Yuzhno-Sakhalinsk］ |
| UV［ultraviolet; ultraviolet rays］ |
| UV カット商品［(和) ultraviolet rays＋cut］ |
| UV フィルター［ultraviolet filter］ |
| UV 分析［unemployment-vacancy analysis］ |
| UV-A［ultraviolet-A］ |
| UV-B［ultraviolet-B］ |
| UV-C［ultraviolet-C］ |
| UX［utility X］ |
| UY［Oriental Republic of Uruguay］ |
| UZ［Republic of Uzbekistan］ |
| UZB［Republic of Uzbekistan］ |