| U | Uranium |
| U | Uniform |
| U | University of Utah |
| U | Uracil |
| u | Unified atomic mass unit |
| U-boat | Undersea-boat |
| u/s | under section |
| U/S | UltraSound |
| UAC | User Account Control |
| UAC | United American Committee |
| UAE | United Arab Emirates |
| UAE | Emirates |
| UAE | Uterine Artery Embolization |
| UAE | Université Abdelmalek Essaadi |
| UAE | Unix Amiga Emulator |
| UAE | Unrecoverable Application Error |
| UAMCCO | United Aluminum & Metal Coating Company |
| UARFCN | UTRA Absolute Radio Frequency Channel Number |
| UAS | User Agent Server |
| UAS | Ukrainian Academy of Sciences |
| UAS | University of Alaska Southeast |
| UAS | Unmanned Aircraft System |
| UAS | University of Agricultural Sciences |
| UAV | Unmanned Aerial Vehicle |
| UBSE | Uttarakhand Board of Secondary Education |
| Ubuntu | from the Zulu word (ùɓúntú) that translates as “humanity towards others” |
| UCB | University of California, Berkeley |
| UCB | Union Chimique Belge |
| UCB | University of Colorado Boulder |
| UCB | University College Birmingham |
| UCB | Universidade Católica de Brasília |
| UCB | University College of Bahrain |
| UCB | Uganda Commercial Bank |
| UCB | Union des Communistes Burkinabè |
| UCB | Universidad Central de Bayamón |
| UCB | United Carolina Bank |
| UCEED | Undergraduate Common Entrance Exam for Design |
| UCLA | University of California, Los Angeles |
| UCLA | Universidad Centroccidental Lisandro Alvarado |
| UCLA | Uniform Collaborative Law Act |
| UCO | University of Central Oklahoma |
| UCO | United Commercial Bank |
| UCS | Unified Computing System |
| UCS | Universal Character Set |
| UCS | University Campus Suffolk |
| UCS | Union of Concerned Scientists |
| UCS | University College School |
| UDA | Urban Development Authority |
| UDA | Upper Deck Authenticated |
| UDA | Unified Driver Architecture |
| UDA | UnDocumented Alien |
| UDA | Union Des Artistes |
| UDA | Unión Deportivo Ascensión |
| UDA | Ulster Defence Association |
| UDA | Universidad De Atacama |
| UDA | Union for Democratic Action |
| UDA | United Democratic Alliance |
| UDA | Université Des Ainés |
| UdA | Université d’Auvergne |
| UDA | United Democratic Alliance |
| UDC | University of the District of Columbia |
| UDF | User-Defined Function |
| UDF | United Democratic Front |
| UDF | Universal Disk Format |
| UDF | United Dairy Farmers |
| UDF | Union pour la Démocratie Française |
| UDF | United Democratic Front |
| UDF | Uniqueness Database File |
| UDF | United Democratic Forces |
| UDF | United Democratic Front |
| UDID | Unique Device Identifier |
| UDID | Unit for Development in Intellectual Disabilities |
| UDMA | Ultra Direct Memory Access |
| UDMA | Urethane Dimethacrylate |
| UDMA | Union Démocratique du Manifeste Algérien |
| UDP | User Datagram Protocol |
| UDP | Uridine diphosphate |
| UDP | Unit Deployment Program |
| UDP | United Democratic Party |
| UDP | Ulster Democratic Party |
| UDP | United Democratic Party |
| UDP | United Democratic Party |
| UDP | Unidad Democrática y Popular |
| UDP | União Democrática Popular |
| UDP | Usenet Death Penalty |
| UE4 | Unreal Engine 4 |
| UEFA | Union of European Football Associations |
| UEFI | Unified Extensible Firmware Interface |
| UFC | Ultimate Fighting Championship |
| UFC | Universidade Federal do Ceará |
| UFC | University of Franche-Comté |
| UFC | Urinary Free Cortisol |
| UFC | Ukrainian Fruit Company |
| UFDA | USB Flash Drive Alliance |
| UFEI | Urban Forest Ecosystems Institute |
| UFO | Unidentified Flying Object |
| UFS | Universal Flash Storage |
| UFS | Universidade Federal de Sergipe |
| UFS | University of the Free State |
| UFS | United Feature Syndicate |
| UFS | Unix File System |
| UFS | Universal Fighting System |
| UFS | Domtar Corporation |
| UFS | Universal Frame System |
| UFS | Union of Finance Staff |
| UG | Uganda |
| UG | Undergraduate |
| ug | Uganda |
| UG | Underground |
| UG | University of Ghana |
| Ugadi | the beginning of a new age |
| UGC | User Generated Content |
| UGC | University Grants Commission |
| UGC | University Grants Committee |
| UGC | Unipart Group of Companies |
| UHBVN | Uttar Haryana Bijli Vitran Nigam |
| UHF | Ultra High Frequency |
| UHF | Unrestricted Hartree–Fock |
| UHF | United Hospital Fund |
| UHF | United Housing Foundation |
| UHT | Ultra-High Temperature |
| UHT | Universal Health Realty Income Trust |
| UHT | Unterstützungs-Hubschrauber Tiger |
| UHT | Ukrainian High Technologies |
| UI | User Interface |
| UI | Universitas Indonesia |
| UI | University of Ibadan |
| UI | University of Illinois |
| UI | Urinary Incontinence |
| UI | Unemployment Insurance |
| UI | University of Idaho |
| UI | University of Iceland |
| UI | University of Iowa |
| UI | University of Isfahan |
| UI | United Illuminating |
| UI | Unit Interval |
| UI | Unité Internationale |
| UI | Unit Injector |
| UI | Eurocypria Airlines |
| UI | Universal Indicator |
| UI | Utility Infielder |
| UI | Unix International |
| UI | University of Incheon |
| UI | University of Innsbruck |
| UI | Universities Ireland |
| UICC | Universal Integrated Circuit Card |
| UICC | Union for International Cancer Control |
| UICC | United Irish Cultural Center |
| UID | Unique Identification |
| UID | User Identifier |
| UID | Unitedworld Institute of Design |
| UID | Umeå Institute of Design |
| UID | Universal Instructional Design |
| UIDAI | Unique IDentification Authority of India |
| UIM | User Identity Module |
| UIM | Universal Input Method |
| UIM | Union Internationale Motonautique |
| UK | United Kingdom |
| uk | Ukrainian |
| UK | Univerzita Komenského |
| UK | University of Kentucky |
| UK | Uttarakhand |
| uk | United Kingdom (TLD) |
| UK | Vistara |
| UK | Universiteitskrant |
| UK | Univerzita Karlova |
| UK | Université Kongo |
| UK | Universidad Kennedy |
| UK | University of Kashmir |
| UK | University of Kara |
| UKAS | United Kingdom Accreditation Service |
| UKAS | Unit Kerjasama Awam Swasta |
| UKG | Upper Kindergarten |
| UL | Underwriters Laboratories |
| ul | Unordered Lists |
| UL | Universal Life |
| UL | Unilever |
| UL | University of Lisbon |
| UL | University of Louisiana |
| UL | University of Louisville |
| ULA | United Launch Alliance |
| ULA | Universidad de Los Andes |
| ULA | Universidad LatinoAmericana |
| ULA | Uncommitted Logic Array |
| ULA | Unique Local Address |
| ULA | User License Agreement |
| ula | Fungwa |
| ULA | United Left Alliance |
| ULA | Underground Literary Alliance |
| ULFA | University of Lethbridge Faculty Association |
| ULFA | United Liberation Front of Assam |
| ULPA | Ultra Low Penetration Air |
| ULPA | Uniform Limited Partnership Act |
| ULPA | United Lightning Protection Association |
| ULSI | Ultra-Large Scale Integration |
| UMANG | Unified Mobile Application for New-age Governance |
| UMAR | United Methodist Agency for the Retarded |
| UMDNJ | University of Medicine and Dentistry of New Jersey |
| UMPP | Ultra Mega Power Project |
| UMS | Universiti Malaysia Sabah |
| UMS | Universal Media Studios |
| UMS | Universitas Muhammadiyah Surakarta |
| UMS | USB Mass Storage |
| UMS | Unité Mixte de Service |
| UMS | Unified Messaging System |
| UMS | Ulnar–Mammary Syndrome |
| UMS | Uniform Mark Scale |
| UMS | Universal Media Server |
| UMS | University of Maine System |
| UMS | University Management System |
| UMS | United Mexican States |
| UMS | Urgent Mail Service |
| UMS | Universal Mobile Systems |
| UMT | Universiti Malaysia Terengganu |
| UMT | University of Management and Technology |
| UMT | University of Management and Technology |
| UMT | Union Marocaine du Travail |
| UMT | University of Montana |
| UMT | Universiteti Metropolitan Tirana |
| UMT | United Mobility Technology |
| UMTRI | University of Michigan Transportation Research Institute |
| UMTS | Universal Mobile Telecommunications System |
| UN | United Nations |
| UNAIDS | United Nations Programme on HIV and AIDS |
| UNAMA | United Nations Assistance Mission in Afghanistan |
| UNAMID | United Nations Hybrid Operation in Darfur |
| UNCDF | United Nations Capital Development Fund |
| UNCTAD | United Nations Conference on Trade And Development |
| UNDOF | United Nations Disengagement Observer Force |
| UNDP | United New Democratic Party |
| UNDP | United National Democratic Party |
| UNDP | United Nations Development Programme |
| UNECE | United Nations Economic Commission for Europe |
| UNEP | United Nations Environment Programme |
| UNEP | United National Empowerment Party |
| UNESCO | United Nations Educational, Scientific and Cultural Organization |
| UNFPA | United Nations Population Fund |
| UNHCR | United Nations High Commissioner for Refugees |
| UNICEF | United Nations Children’s Fund |
| UNIFEM | Fonds de développement des Nations unies pour la femme |
| UNIFIL | United Nations Interim Force in Lebanon |
| UNII | Unlicensed National Information Infrastructure |
| UNII | UNique Ingredient Identifier |
| UNII | Undistributed Net Investment Income |
| UNII | Yeniseysk Airport |
| UNILEC | United Electrical Industries |
| Unimog | Universal-Motor-Gerät |
| Uninor | Composed of the names Unitech and Telenor, the two owners of the joint venture |
| Univ | University |
| UNIVAC | UNIVersal Automatic Computer |
| UNIX | Uniplexed Information and Computing Service |
| UNMIL | United Nations Mission in Liberia |
| UNMISS | United Nations Mission in South Sudan |
| UNMOGIP | United Nations Military Observer Group in India and Pakistan |
| UNO | University of New Orleans |
| UNO | United Nations Organization |
| UNODC | United Nations Office on Drugs and Crime |
| UNOLS | University-National Oceanographic Laboratory System |
| UNSTAMIH | United Nations Stabilisation Mission In Haiti |
| UNTSO | United Nations Truce Supervision Organization |
| UP | Uttar Pradesh |
| UP | Union Pacific Railroad |
| UP | University of Pretoria |
| UP | Upper Peninsula |
| UP | University of Pennsylvania |
| UP | University of Portland |
| UP | University of the Philippines |
| UP | Uplifting Entertainment |
| UP | Universidade do Porto |
| UP | Universidad del Pacífico |
| UP | Université de Poitiers |
| UP | Urticaria Pigmentosa |
| UP | United Party |
| UPA | United Progressive Alliance |
| UPA | Union des Producteurs Agricoles |
| UPA | Usability Professionals’ Association |
| UPA | United States Professional Poolplayers Association |
| UPA | Uniform Partnership Act |
| UPA | United Productions of America |
| UPA | Ultra Port Architecture |
| UPA | Universal Powerline Association |
| UPA | Unique Particle Attribution |
| UPA | Utenti Pubblicità Associati |
| UPA | University Preparatory Academy |
| UPA | University Press of America |
| UPA | Uganda People’s Army |
| UPA | União dos Povos de Angola |
| UPC | Universal Product Code |
| UPC | Uplink Power Control |
| UPC | United Poultry Concerns |
| UPC | Unique Porting Code |
| UPC | Uganda People’s Congress |
| UPenn | University of Pennsylvania |
| UPI | Unified Payment Interface |
| UPI | United Press International |
| UPI | Universal Pictures International |
| UPI | Universitas Pendidikan Indonesia |
| UPI | University Physicians, Inc. |
| UPI | Uteroplacental Insufficiency |
| UPI | Unique Patient Identifier |
| UPI | United Promotions Inc. |
| UPI | Unione delle Province Italiane |
| UPI | User Programmatic Interface |
| UPI | Ulcer Performance Index |
| UPI | Ural Polytechnic Institute |
| UPnP | Universal Plug and Play |
| UPOV | International Union for the Protection of New Varieties of Plants |
| UPP | Ubiquitin-Proteasome Pathway |
| UPP | Uttar Pradesh Police |
| UPP | Pacifying Police Unit |
| UPP | Ultimate++ |
| UPP | Ultimate Picture Palace |
| UPP | Unión Por el Perú |
| UPP | University Partnership Programme |
| UPP | Upolu Airport |
| UPP | União Promotora para o Progresso |
| UPP | United Progressive Party |
| UPP | United People’s Party |
| UPP | United People’s Party |
| UPP | Urethral Pressure Profile |
| UPP | University of Pittsburgh Press |
| UPP | Unified Progressive Party |
| UPP | United Progressive Party |
| UPP | United Peoples Party |
| UPP | United People’s Party |
| UPP | United People’s Party |
| UPP | United People’s Party |
| UPP | United People’s Party |
| UPPSC | Uttar Pradesh Public Service Commission |
| UPS | Uninterruptible Power Supply |
| UPS | United Parcel Service |
| UPS | Ultraviolet Photoelectron Spectroscopy |
| UPS | Université Paul Sabatier |
| UPS | University of Puget Sound |
| UPS | Universal Polar Stereographic |
| UPSC | Union Public Service Commission |
| UPSC | Umea Plant Science Centre |
| UPSC | Urban Planning Society of China |
| UPSEE | Uttar Pradesh State Entrance Exam |
| UPSRTC | Uttar Pradesh State Road Transport Corporation |
| UPSSSC | Uttar Pradesh Subordinate Services Selection Commission |
| UPTU | Uttar Pradesh Technical University |
| uPVC | Unplasticized Polyvinyl Chloride |
| URDIP | Unit for Research and Development of Information Product |
| URI | Uniform Resource Identifier |
| URL | Uniform Resource Locator |
| URL | Universitat Ramon Llull |
| URL | Underground Racing League |
| URL | Universidad Rafael Landívar |
| URN | Uniform Resource Name |
| URN | Update Request Number |
| URN | Unit Reference Number |
| URN | Undergraduate Research Network |
| URN | University Radio Nottingham |
| US | United States |
| US | Ultrasound |
| US | Universidad de Sevilla |
| US | US Airways |
| us | United States (TLD) |
| US | University of Sussex |
| US | Universiteit Stellenbosch |
| US | Université de Sherbrooke |
| US | Uniwersytet Szczeciński |
| US | University of Salzburg |
| US | University School |
| US | United Services |
| US | Urgences-Santé |
| USA | United States of America |
| USA | United States Army |
| USA | United Space Alliance |
| USA | University of South Alabama |
| USA | Union of South Africa |
| USA | Uniform Securities Act |
| USA | University of South Asia |
| USA | Underground Service Alert |
| USA | United Soccer Association |
| USA | United Scenic Artists |
| USA | Concord-Padgett Regional Airport |
| USA | Université Sainte-Anne |
| USA | Unionville-Sebewaing Area |
| USA | United Seniors Association |
| USA | United Supermarkets Arena |
| USA | United Student Aid |
| USAID | United States Agency for International Development |
| USB | Universal Serial Bus |
| USB PD | USB Power Delivery |
| USB-C | Universal Serial Bus Type-C |
| USB-IF | USB Implementers Forum |
| USBT | University School of Biotechnology |
| USCENTCOM | United States Central Command |
| USD | United States Dollar |
| USD | University of San Diego |
| USD | Unified School District |
| USD | Upside-Down |
| USD | University of South Dakota |
| USD | Ultrasonic Silent Drive |
| USDA | United States Department of Agriculture |
| USDA | Union Solidarity and Development Association |
| USDA | United Sabah Dusun Association |
| USDOD | United States Department of Defense |
| USIM | User Services Identity Module |
| USIM | Universiti Sains Islam Malaysia |
| USIM | US Intermodal Maritime Inc |
| USMC | United States Marine Corps |
| USMC | United Shoe Machinery Corporation |
| USOCA | Uttarakhand State Organic Certification Agency |
| USP | Unique Selling Proposition |
| USP | University of the South Pacific |
| USP | United States Pharmacopeia |
| USP | University of Sao Paulo |
| USP | Unité Spéciale de la Police |
| USP | United States Penitentiary |
| USP | Universal Stress Protein |
| USP | Universal Storage Platform |
| USP | Utah State Prison |
| USP | Unified Settlement Planning |
| USP | Uttama Seva Padakkama |
| USP | Universal Space Platform |
| USPA | United States Polo Association |
| USPA | United States Parachute Association |
| USPA | United States Permafrost Association |
| USPACFLT | United States Pacific Fleet |
| USPACOM | United States Pacific Command |
| USPS | United States Postal Service |
| USPS | United States Power Squadrons |
| USPTO | United States Patent and Trademark Office |
| USSD | Unstructured Supplementary Service Data |
| USSD | United Studios of Self Defense |
| USSD | United States Society on Dams |
| USSR | Union of Soviet Socialist Republics |
| USSR | Uninterrupted Sustained Silent Reading |
| USTOA | United States Tour Operators Association |
| UTC | Coordinated Universal Time |
| UTC | United Technologies Corporation |
| UTC | United Theological College |
| UTC | Unit Type Code |
| UTC | University of Tennessee at Chattanooga |
| UTC | United Theological Seminary |
| UTF | Unicode Transformation Format |
| UTF | University of Tokyo Forests |
| UTF | Urban Taskforce |
| UTGST | Union Territory Goods and Services Tax |
| UTH | University of Texas-Houston |
| UTH | Udon Thani International Airport |
| UTH | University Teaching Hospital |
| UTH | University of Thessaly |
| UTH | Up The Hoods |
| UTH | Umbilical Termination Head |
| Uth | Untrihexium |
| UTI | Urinary Tract Infection |
| UTI | Universal Technical Institute |
| UTI | Unit Trust of India |
| UTI | Uniform Type Identifier |
| UTI | Unique Transaction Identifier |
| UTI | Ultrasound Tongue Imaging |
| UTP | Unshielded Twisted pair |
| UTR | Untranslated Region |
| UTR | Unique Taxpayer Reference |
| UTR | Unique Transaction Reference |
| UTR | Universal Tennis Rating |
| UTR | Uttaradit Airport |
| UTR | Ukrainian Television and Radio |
| UTR | Union of Translators of Russia |
| UTRAN | UMTS Terrestrial Radio Access Network |
| UTU | United Transportation Union |
| UTU | Uttarakhand Technical University |
| UTU | Ulster Teachers Union |
| UTU | University Teachers Union |
| UTU | Ustupo Airport |
| UTV | Utility Terrain Vehicle |
| UTV | Ulster TeleVision |
| UV | UltraViolet |
| UV | Universidad Veracruzana |
| UV | Union Valenciana |
| UVC | Ultraviolet C |
| UVC | USB Video Class |
| UVC | Uniform Vehicle Code |
| UVC | Umbilical Venous Catheter |
| UVEPROM | Ultra-Violet Erasable Programmable Read Only Memory |
| UWB | Ultra-Wide Band |
| UWB | University of Washington Bothell |
| UWB | University of Wales, Bangor |
| UWB | University of West Bohemia |
| UX | User eXperience |
| ux | Uxor |
| UX | Air Europa |
| UYSM | Uttam Yudh Seva Medal |
