| University of Texas at Austin | University of the Arts London | University of Toronto |
| University Of Tripoli Lebanon | University of tromso | University of Ulm |
| University of Washington | University of Waterloo | University of Wisconsin |
| University of York | University Park, Illinois | University Park, Iowa |
| University Park, Maryland | Unix | UNIX |
| Unix File System | Unix filesystem | Unix philosophy |
| Unix shell | UNIX System III | UNIX System V |
| Unix wars | Unix-Like | Unix-like |
| Unknown (2011 film) | Unknown Berlin Gospel | Unknown Soldier Memorial (Egypt) |
| Unladen Swallow | Unlicensed assistive personnel | Unmanned aerial vehicle |
| Unmanned combat aerial vehicle | Unmanned combat air vehicle | Unmanned ground vehicle |
| UNMIK Travel Document | Unnatural Causes: Is Inequality Making Us Sick? | Unnur Birna Vilhjálmsdóttir |
| Uno (card game) | Uno (dicycle) | Uno Cygnaeus |
| Unobtrusive JavaScript | UNODC | Unparser |
| UNPD | UNPO | Unpowered flight |
| Unreachable memory | Unreal 3 | Unreal Engine |
| Unreal Engine 3 | Unreal Tournament | Unrepresented Nations and Peoples Organization |
| Unrequited love | Unrestricted submarine warfare | Unsaturated fat |
| Unsaturated hydrocarbon | Unschooling | UNSMIL |
| Unstoppable (2010 film) | Unstructured data | UNStudio |
| Unsupervised learning | Untangle | Unter den Linden |
| Unterfranken | Unterfranken (region) | Unterhaltungssoftware Selbstkontrolle |
| Untermensch | Until Dawn | Untraceable |
| Ununennium | Ununhexium | Ununoctium |
| Ununpentium | Ununquadium | Ununseptium |
| Ununtrium | UNWTO | UO2 |
| UP | Up (2009 film) | UP (complexity) |
| Up antiquark | Up Close & Personal | Up in the Air (2009 film) |
| Up quark | Up2data | Up2date |
| Upalite | Upanishads | Upcycling |
| Upernavik Airport | Upgrade | Upham, North Dakota |
| Upham, Wisconsin | UPI | Upland, Nebraska |
| Uplands Park, Missouri | Upleward | UPnP |
| Upper alimentary tract | Upper Aulaqi Sheikhdom | Upper Austria |
| Upper Brookville, New York | Upper Cambrian | Upper class |
| Upper Devonian | Upper extremity | Upper extremity of femur |
| Upper extremity of humerus | Upper extremity of radius | Upper gastrointestinal bleed |
| Upper gastrointestinal bleeding | Upper Kalskag, Alaska | Upper limb |
| Upper Marlboro, Maryland | Upper Nyack, New York | Upper Ordovician |
| Upper Palatinate | Upper Permian | Upper Pleistocene |
| Upper respiratory tract | Upper respiratory tract infection | Upper-atmospheric lightning |
| Uprising (2001 film) | UPS Airlines | UPS Airlines Flight 1354 |
| UPS Airlines Flight 6 | Upsala, Minnesota | Upselling |
| Upside-down catfish | Upsilon meson | Upsilon Scorpii |
| UpToDate | Uptodown | Upton Sinclair |
| Upton, Kentucky | Upton, Wyoming | UPU |
| Upupa africana | Upupa antaios | Upupa epops |
| Upward communication | Upwelling | Upwork |
| UPX | Uqba ibn Nafi | Urachal cyst |
| Urachus | Uracil | Urals |
| Uralvagonzavod | Uranian | Uraninite |
| Uranium | Uranium carbide | Uranium hexafluoride |
| Uranium in the environment | Uranium pentafluoride | Uranium(VI) fluoride |
| Uranium-233 | Uranium-235 | Uranium-238 |
| Urara Takano | Urartu | Urate oxidase |
| Urawa Red Diamonds | Urb. | Urbain Le Verrier |
| Urban agglomeration | Urban agriculture | Urban area |
| Urban climate | Urban districts of Germany | Urban heat island |
| Urban legend | Urban Lesjak | Urban lumberjacking |
| Urban Partnership Bank | Urban semiotics | Urban sprawl |
| Urban township | Urban warfare | Urban-type settlement |
| Urbana, Illinois | Urbana, Iowa | Urbancrest, Ohio |
| Urbandale, Iowa | Urbanization | Urbanized Area |
| Urbank, Minnesota | Urbano Rattazzi | Urbeis |
| Urby Emanuelson | Urdu | Urdu Wikipedia |
| Urea | Urea cycle | Urea cycle disorder |
| Urease | Urech hydantoin synthesis | Urechis unicinctus |
| Ureidopenicillin | Uremia | Urenco Group |
| Ureter | Ureteral branches of renal artery | Ureteritis |
| Urethra | Urethral artery | Urethritis |
| Urginea maritima | Urho Kekkonen | URI |
| Uri Ariel | Uri Avnery | Uri Davis |
| Uri Gavriel | Uri Maklev | Uri Sebag |
| Uric acid | Uriel da Costa | Urinal |
| Urinary bladder | Urinary bladder cancer | Urinary catheterization |
| Urinary incontinence | Urinary meatus | Urinary retention |
| Urinary system | Urinary tract infection | Urinary urgency |
| Urination | Urine | Urine anion gap |
| Urine osmolality | URL | Url |
| URL redirection | URL shortening | URLTEAM |
| Urmatt | Urmila Matondkar | Urnfield culture |
| Urochloa | Urochloa leersioides | Urochloa mutica |
| Urochloa reptans | Urochordata | Urocolius |
| Urocolius indicus | Urocolius macrourus | Urocyon cinereoargenteus |
| Urocyon littoralis | Urodela | Urogenital tuberculosis |
| Urohidrosis | Urokinase | Urolagnia |
| Urology | Uromastyx | Uromastyx aegyptia |
| Uromastyx benti | Uromastyx leptieni | Uromastyx loricata |
| Uromastyx ornata | Uromastyx thomasi | Uromastyx yemenensis |
| Uropodidae | Uropsilus | Uropsilus andersoni |
| Uropsilus gracilis | Uropsilus investigator | Uropsilus soricipes |
| Uropygi | Uros Slokar | Urospermum |
| Urospermum dalechampii | Urospermum echioides | Urospermum grandiflorum |
| Urospermum picroides | Urothelial papilloma | Urs Meier |
| Urs Widmer | Ursa Major | Ursa Major II Dwarf |
| Ursa Major Moving Group | Ursa Minor | Ursa Minor Dwarf |
| Ursa, Illinois | Ursidae | Ursolic acid |
| Ursula Holl | Ursula K. Le Guin | Ursula von der Leyen |
| Ursus | Ursus americanus | Ursus americanus cinnamomum |
| Ursus americanus kermodei | Ursus arctos | Ursus arctos arctos |
