| TEVA | Tutmonda Esperantista Vegetarana Asocio | In Esperanto | → Associations → Nutrition |
| TNT | Trinitrotolueno = TNT | Trinitrotoluol | In German = TNT | Trinitrotoluè | In Catalan = TNT | Trinitrotoluen | In Czech = TNT | Trinitrotoluene | In English = TNT | Trinitrotolueno | In Spanish = TNT | Trinitrotoluenori | In Basque = TNT | ترینیتروتولوئن | In Persian = TNT | Trinitrotoluène | In French = TNT | Trinitrotoluene | In Italian = TNT | Trinitrotoluolas | In Lithuanian = TNT | Trinitrotolueen | In Dutch = TNT | Trinitrotoluen | In Nynorsk = TNT | Trinitrotoluen | In Norwegian = TNT | Trinitrotolueno | In Portuguese = TNT | Trinitrotoluen | In Romanian = TNT | Тринитротолуол | In Russian = TNT | Trinitrotoluen | In Slovenian = ТНТ | Тринитротоулен | In Serbian = TNT | ทีเอ็นที | In Thai = TNT | Trinitrotoluen | In Turkish = ТНТ | Тринітротолуол | In Ukrainian |
In Esperanto | → Chemicals → Military engineering |
| TOLE | Tutmonda Ortodoksa Ligo Esperantista | In Esperanto | → Organizations and associations → 271 |
| TT | TEJO-Tutmonde | In Esperanto | → Serial publications, periodicals |
| TTT | Tut-Tera Teksaĵo = WWW | World Wide Web | In English |
In Esperanto | → Internet |
| TTT | Teatro Trupo de Tuluzo | In Esperanto | → Organizations and associations → Theatre |
| U | Uranio = U | Uranium | In French = U | Uran | ALS = U | يورانيوم | In French = U | Uran | In Azerbaijani = U | Уран | In Belarusian = U | Уран | In Bulgarian = U | ইউরেনিয়াম | In Bengali = U | Uranijum | In Bosnian = U | Urani | In Catalan = U | Uraniu | In Corsican = U | Uran | In Czech = U | Uran | In Danish = U | Uran | In German = U | Ουράνιο | In Greek = U | Uranium | In English = U | Uranio | In Spanish = U | Uraan | In Estonian = U | Uranio | In Basque = U | اورانیوم | In Persian = U | Uraani | In Finnish = U | Urani | In Friulian = U | Uranio | In Galician = U | אורניום | In Hebrew = U | Uranij | In Croatian = U | Iranyòm | HT = U | Urán | In Hungarian = U | Ուրան (տարր) | In Armenian = U | Uranium | In Indonesian = U | Uranio | In Ido = U | Úran | In Icelandic = U | Uranio | In Italian = U | ウラン | In Japanese = U | jinmrvurani | JBO = U | ಯುರೇನಿಯಮ್ | KN = U | 우라늄 | In Korean = U | Uranium | In Latin = U | Uran | In Letzeburgesh = U | Uranas | In Lithuanian = U | Urāns | In Latvian = U | യുറേനിയം | In Malayalam = U | Ilhuicateōtepoztli | En Nahuatl = U | Uran | NDS = U | Uranium | In Dutch = U | Uran | In Nynorsk = U | Uran | In Norwegian = U | Uran | In Polish = U | Urânio | In Portuguese = U | Uranyu | In Quechua = U | Uraniu | In Romanian = U | Уран | In Russian = U | यूरानियम | In Sanskrit = U | Uraniu | In Sicilian = U | Uranijum | In Serbo-Croatian = U | Urán | In Slovak = U | Uran | In Slovenian = U | Urani | SQ = U | Уранијум | In Serbian = U | Uran | In Swedish = U | Urani | In Swahili = U | யுரேனியம் | In Tamil = U | ยูเรเนียม | In Thai = U | Uranyo | In Tagalog = U | Uranyum | In Turkish = U | Уран | In Ukrainian = U | Urani | In Vietnamese = U | 鈾 | In Chinese |
In Esperanto | → Chemistry |
| UALE | Universala Artista Ligo de Esperantistoj | In Esperanto | → Organizations and associations → Arts |
| UDHR | Universala Deklaracio pri la Homaj Rajtoj | In Esperanto | → Politics |
| UDHR | Universala Deklaracio de Homaj Rajtoj | In Esperanto | → Politics |
| UDK | Universala Dekuma Klasifiko = UDC | Universal Decimal Classification | In English = CDU | Classification Décimale Universelle | In French = UDC | Universele Decimale Classificatie | In Dutch = CDU | Clasificación Decimal Universal | In Spanish = UDC | Universel Decimal Classifikation | In Danish |
In Esperanto | → Libraries |
| UEA | Universala Esperanto Asocio (www.uea.org) | In Esperanto | → Associations |
| UEF | Unio de la Europaj Federistoj = UEF | Union of European Federalists | In English |
In Esperanto | → Political parties and movements |
| UEL | Urala Esperanto-Ligo | In Esperanto | → Organizations and associations |
| UES | Urala Esperanto-Societo | In Esperanto | → Organizations and associations |
| UFE | Unifio Franca por Esperanto (http://esperanto-france.org) = UFE | Union Française pour l'Espéranto | In French |
In Esperanto | → Organizations and associations |
| UIEA | Universala Islama Esperanto-Asocio | In Esperanto | → Associations → Islam |
| UK | Universala Kongreso | In Esperanto | → Organizations and associations |
| UKrEA | Ukraina Esperanto-Asocio | In Esperanto | → Associations |
| ULEJ | Ukrainia Ligo de Esperantista Junularo | In Esperanto | → Organizations and associations |
| UMEA | Universala Medicina Esperanto Asocio | In Esperanto | → Associations → Medicine |
| UN | Unuigintaj Nacioj (www.un.org) = ONU | Organisation des Nations Unies | In French = ONU | Organizazión d'as Nazions Unitas | In Aragonese = ААН | Арганіза́цыя Аб'ядна́ных На́цый | In Belarusian = VN | Verenigde Nasies | In Afrikaans = ONU | Organización de les Naciones Uníes | In Asturian = OOH | Организацията на обединените нации | In Bulgarian = ABU | Aozadur ar Broadoù Unanet | In Breton = ПНО | Пĕрлешнĕ Нацисен Организацийĕ | In Chuvash = FN | Feriene Naasjes | In Frisian = UN | United Nations | In English = NBE | Nazio Batuen Erakundea | In Basque = ONU | Organización das Nacións Unidas | In Occitan = UN | Unuiĝinta Naciaro | In Esperanto = UN | Ujedinjeni Narodi | In Bosnian = CN | Consociatio Nationum | In Latin = FN | Forenede Nationer | In Danish = UN | Unionita Nacioni | In Ido = ONU | Organizzazione delle Nazioni Unite | In Italian = KU | Kenedhlow Unys | In Cornish = ONU | Organització de les Nacions Unides | In Catalan = ΟΗΕ | Οργανισμός Ηνωμένων Εθνών | In Greek = ΗΕ | Ηνωμένα Έθνη | In Greek = ONU | Organización de las Naciones Unidas | In Spanish = VN | Vereinte Nationen | In German = VN | Verenigde Naties | In Dutch = VN | Vereent Natiounen | In Letzeburgesh = ООН | Организация Oбъединённых Hаций | In Russian = ONU | Organisacion des Nacions unies | FRP = ONZ | Organizacja Narodów Zjednoczonych | In Polish = BMT | Birlashgan Millatlar Tashkiloti | In Uzbek = ООН | Організація Об'єднаних Націй | In Ukrainian = BM | Birleşmiş Milletler | In Turkish = LHiQ | Liên Hiệp Quốc | In Vietnamese = OKB | Organizata e Kombeve të Bashkuara | In Albanian = OSN | Organizácia Spojených národov | In Slovak = OZN | Organizacija Združenih Narodov | In Slovenian = УН | Уједињене нације | In Serbian = FN | Förenta nationerna | In Swedish = UM | Umoja wa Mataifa | In Swahili = NU | Nazzioni Uniti | In Sicilian = ONU | Organizaţia Naţiunilor Unite | In Romanian = ONU | Organização das Nações Unidas | In Portuguese = VN | Vereenten Natschonen | NDS = ST | Sameindu Tjóðir | In Faroese = HN | Huñusqa Nasyunkuna | In Quechua = PBB | Pertubuhan Bangsa-bangsa Bersatu | In Malay = NA | Náisiúin Aontaithe | In Irish = ÜRO | Ühinenud Rahvaste Organisatsioon | In Estonian = SÞ | Sameinuðu þjóðanna | In Icelandic |
In Esperanto | → International relations → United Nations |
| UN | Unuiĝinta Naciaro (www.un.org) = ONU, ААН, VN, OOH, ABU, ПНО, FN, NBE, CN, KU, ΟΗΕ, ООН, ONZ, BMT, LHiQ, OKB, OSN, OZN, УН, UM, ST, HN, PBB, NA, ÜRO, SÞ (look above) |
In Esperanto | → International relations → United Nations |
| UPU | Universala Poŝt-Unio = UPU | Union Postale Universelle | In French = UPU | Universal Postal Union | In English |
In Esperanto | → International relations → Transport and postal services |
| USE | Universala Slipa Enciklopedio | In Esperanto | → General encyclopaedias |
| USEJ | Usona Esperantista Junularo (http://usej.org) | In Esperanto | → Organizations and associations |
| USSR | Unio de Sovetaj Socialismaj Respublikoj = URSS | Unaniezh ar Republikoù Sokialour Soviedel | In Breton = URSS | Union des Républiques Socialistes Soviétiques | In French = USSR | Unie van Sosialistiese Sowjetrepublieke | In Afrikaans = USSR | Union of Soviet Socialist Republics | In English = СССР | Сою́з Сове́тских Социалисти́ческих Респу́блик | In Russian = CCCP | Съюзът на съветските социалистически републики | In Bulgarian = SSSR | Soyuz Sovetskikh Sotsialisticheskikh Respublik | In Russian = URSS | Unión de Republicas Sozialistas Sobieticas | In Aragonese = XRSS | Xunión de les Repúbliques Socialistes Soviétiques | In Asturian = SSRİ | Sovet Sosialist Respublikaları İttifaqı | In Azerbaijani = TSRS | Tarybu Socialistiniu Respubliku Sajunga | In Baltic languages = SSSR | Savez Sovjetskih Socijalističkih Republika | In Serbo-Croatian = URSS | Unió de Repúbliques Socialistes Soviètiques | In Catalan = SSSR | Svaz sovětských socialistických republik | In Czech = CCCP | Социаллă Совет Республикисен Союзĕ | In Chuvash = USSR | Unionen af Socialistiske Sovjetrepublikker | In Danish = URSS | Unione delle Repubbliche Socialiste Sovietiche | In Italian = ZSRR | Związek Socjalistycznych Republik Radzieckich | In Polish = SSKS | Szovjet Szocialista Köztársaságok Szövetsége | In Hungarian = UdSSR | Union der Sozialistischen Sowjetrepubliken | In German = ΕΣΣΔ | Ένωση Σοβιετικών Σοσιαλιστικών Δημοκρατιών | In Greek = URSS | Unión de Repúblicas Socialistas Soviéticas | In Spanish = NSVL | Nõukogude Sotsialistlike Vabariikide Liit | In Estonian = SESB | Sobietar Errepublika Sozialisten Batasuna | In Basque = USSR | Uny fan Sosjalistyske Sowjetrepublyken | In Frisian = ԽՍՀՄ | Խորհրդային Սոցիալիստական Հանրապետությունների Միություն | In Armenian = URSS | Unión das Repúblicas Socialistas Soviéticas | In Galician = სსრკ | საბჭოთა სოციალისტური რესპუბლიკების კავშირი | In Georgian = URSS | Unio Rerum Publicarum Socialisticarum Sovieticarum | In Latin = CCPC | Советтик Социалисттик Республикалар Союзу | In Kirghiz = UdSSR | Unioun vun de Sozialistesche Sowjetrepubliken | In Letzeburgesh = PSRS | Padomju Sociālistisko Republiku Savienība | In Latvian = СССР | Сојуз на Советските Социјалистички Републики | In Macedonian = УРСС | Униуня Републичилор советиче Сочиалисте | In Moldavan = KRSS | Kesatuan Republik Sosialis Soviet | In Malay = USSR | Unie van Socialistische Sovjetrepublieken | In Dutch = SSSR | Sambandet av Sosialistiske Sovjet-Republikkar | In Nynorsk = SSSR | Samveldet av sovjetiske sosialistrepublikker | In Norwegian = URSS | Unnion d'Républyiques Socialistes Soviétiques | In Norman = URSS | União das Repúblicas Socialistas Soviéticas | In Portuguese = URSS | Union de las Republicas Socialistas Sovieticas | In Occitan = SSRH | Susyalista Suwit Republikakunap Huñun | In Quechua = ССРЦ | Советон Социалистон Республикæты Цæдис | In Ossetian = URSS | Uniunea Republicilor Sovietice Socialiste | In Romanian = URSS | Unioni dî ripùbblichi sucialisti suviètichi | In Sicilian = ZSSR | Zveza sovjetskih socialističnih republik | In Slovenian = СССР | Савез Совјетских Социјалистичких Република | In Serbian = SSCB | Sovyet Sosyalist Cumhuriyetler Birliği | In Turkish = СРСР | Союз Радянських Соціалістичних Республік | In Ukrainian = SSRB | Sovet Sosialistik Republiklar Berlege | In Tatar = SSRI | Sovet Sotsialistik Respublikalar Ittifoqi | In Uzbek |
In Esperanto | → International relations → Geography |
| UTE | Unuiĝo Togolanda por Esperanto | In Esperanto | → Organizations and associations |
| UV | Universala Vortaro | In Esperanto | → Dictionaries |
| V | Valino = V | Valine | In English = V | Valina | In Catalan = V | Valin | In Czech = V | Valin | In Danish = V | Valin | In German = V | Valina | In Spanish = V | Valine | In French = V | 발린 | In Korean = V | Valin | In Croatian = V | Valin | In Indonesian = V | Valina | In Italian = V | :ולין | In Hebrew = V | Valīns | In Latvian = V | Valin | In Letzeburgesh = V | Valinas | In Lithuanian = V | Valine | In Dutch = V | バリン | In Japanese = V | Walina | In Polish = V | Valina | In Portuguese = V | Валин | In Russian = V | Valină | In Romanian = V | Valiini | In Finnish = V | Valin | In Swedish = V | Valin | In Turkish = V | Валін | In Ukrainian = V | 缬氨酸 | In Chinese |
In Esperanto | → Biochemistry, biophysics |
| VD | Vicdelegito | In Esperanto | → Organizations and associations |
| VEA | Venezuela Esperanto-Asocio | In Esperanto | → Associations |
| VEA | Vjetnama Esperanto-Asocio | In Esperanto | → Associations |
| VEB | Virtuala Esperanto-Biblioteko | In Esperanto | → Internet → Libraries |
| VEF | Vintra Esperantista Ferio | In Esperanto | |
| VEJO | Vjetnama Esperantista Junulara Organizo | In Esperanto | → Organizations and associations |
| VEK | Veterana Esperantista Klubo | In Esperanto | → Organizations and associations |
| VEK | Virtuala Esperanto-Kongreso | In Esperanto | → Congresses |
| VEKI | Virtuala Esperanto Kongreso Internacia | In Esperanto | → Networks, communication |
| VUAO | Vjetnama Unio de Amikecaj Organizoj | In Esperanto | → Organizations and associations |
| W | Triptofano = W | Tryptophan | In English = W | ট্রিপ্টোফ্যান | In Bengali = W | Triptòfan | In Catalan = W | Tryptofan | In Danish = W | Tryptophan | In German = W | Triptófano | In Spanish = W | Tryptophane | In French = W | 트립토판 | In Korean = W | Triptofan | In Indonesian = W | Triptofano | In Italian = W | טריפטופן | In Hebrew = W | Triptofāns | In Latvian = W | Tryptophan | In Letzeburgesh = W | Triptofanas | In Lithuanian = W | Tryptofaan | In Dutch = W | トリプトファン | In Japanese = W | Tryptofan | In Norwegian = W | Tryptofan | In Polish = W | Triptófano | In Portuguese = W | Triptofan | In Romanian = W | Триптофан | In Russian = W | Tryptofán | In Slovak = W | Tryptofaani | In Finnish = W | Tryptofan | In Swedish = W | Triptofan | In Turkish = W | Триптофан | In Ukrainian = W | 色氨酸 | In Chinese |
In Esperanto | → Biochemistry, biophysics |
| Y | Tirozino = Y | Tyrosine | In English = Y | تيروسين | In Arabic = Y | Tirosina | In Catalan = Y | Tyrosin | In Danish = Y | Tyrosin | In German = Y | Tirosina | In Spanish = Y | Tyrosine | In French = Y | 티로신 | In Korean = Y | Tirosin | In Indonesian = Y | Tirosina | In Italian = Y | טירוזין | In Hebrew = Y | Tirozīns | In Latvian = Y | Tyrosin | In Letzeburgesh = Y | Tirozinas | In Lithuanian = Y | Tyrosine | In Dutch = Y | ja:チロシン | In Japanese = Y | Tyrozyna | In Polish = Y | Tirosina | In Portuguese = Y | Тирозин | In Russian = Y | Tirosin | SU = Y | Tyrosiini | In Finnish = Y | Tyrosin | In Swedish = Y | Тирозин | In Ukrainian = Y | 酪氨酸 | In Chinese |
In Esperanto | → Biochemistry, biophysics |
| ZEO | Zamenhof-Esperanto Objekto(j) | In Esperanto |