| U Thant | U Thant |
| U-Bahn | Metro |
| U-Boot | U-Boot |
| U-Boot tipo XXI | U-Boot Tipo XXI |
| UA | UA |
| UAAR | Unione degli Atei e degli Agnostici Razionalisti |
| Uaboe | Uaboe |
| Uaiuais | Waiwai |
| Uaiú | Wayuu |
| ualabi | wallaby |
| uapiti | wapiti |
| uau | accidenti |
| Ubaldo Fillol | Ubaldo Fillol |
| Ube | Ube |
| Ubisoft | Ubisoft |
| UBS AG | UBS |
| Ubstadt-Weiher | Ubstadt-Weiher |
| Ubuntu Linux | Ubuntu |
| ubíquo | onnipresente |
| Ucar | Ucar |
| ucase | ukase |
| Uchuu no Stellvia | Uchū no Stellvia |
| Uchão | Spendereccio |
| UCI ProTour | UCI ProTour |
| Uckermark | Uckermark |
| ucraniana | ucraino |
| ucraniano | ucraino |
| Ucrânia | Ucraina |
| Ud | Oud |
| Udanoceratops | Udanoceratops tschizhovi |
| Uday Hussein | Uday Saddam Hussein |
| UDDI | Universal Description Discovery and Integration |
| Udine | Udine |
| Udinese Calcio | Udinese Calcio |
| Udligenswil | Udligenswil |
| Udmurtia | Udmurtia |
| Udmúrtia | Udmurtia |
| Udo Dirkschneider | Udo Dirkschneider |
| Udu-de-coroa-azul | Momotus momota |
| UE Sant Julià | UE Sant Julià |
| Uebeschi | Uebeschi |
| UEFA | UEFA |
| UEFA Futsal Cup | UEFA Futsal Cup |
| Uehlfeld | Uehlfeld |
| Uelen | Uelen |
| Uelzen | Uelzen |
| Uerkheim | Uerkheim |
| Uesslingen-Buch | Uesslingen-Buch |
| Uetendorf | Uetendorf |
| Uetikon am See | Uetikon am See |
| Uezwil | Uezwil |
| ufa | ohi |
| Ufhusen | Ufhusen |
| ufo | UFO |
| Ufo Baby | Ufo baby |
| ufologia | ufologia |
| Uganda | Uganda |
| Ugar | Paraficare |
| ugli-fruit | mapo |
| Ugly Betty | Ugly Betty |
| Ugly Kid Joe | Ugly Kid Joe |
| Ugo Foscolo | Ugo Foscolo |
| Ugo Tognazzi | Ugo Tognazzi |
| uh | buh |
| Uharte-Arakil | Uharte-Arakil |
| UHF | Ultra high frequency |
| Uhingen | Uhingen |
| Uhldingen-Mühlhofen | Uhldingen-Mühlhofen |
| Uhura | Uhura |
| ui | oh |
| uia | accidenti |
| Uilleann pipes | Uilleann pipes |
| Uintatério | Uintatherium |
| uirapuru | scricciolo |
| Uitikon | Uitikon |
| uivar | ruggire |
