| ISD | Internacia Sciencista Dokumentaro | In Esperanto | → Libraries → Mathematics and natural sciences |
| ISE | Internacia Semajnfino Esperantista | In Esperanto | → Congresses |
| ISK | Internacia Scienca Kolegio | In Esperanto | → Mathematics and natural sciences |
| ISTK | Internacia Studumo pri Turismo kaj Kulturo | In Esperanto | → Tourism → Specialized or (poly)technical colleges → Civilization, culture, progress |
| ITK | Internacia Teknika Kolegio | In Esperanto | → Applied sciences, technology |
| ITRE | Internacia Traduk-Reto per Esperanto | In Esperanto | → Organizations and associations → Artificial languages (linguistics) |
| IUPAK | Internacia Unio pri Pura kaj Aplika Kemio |
In Esperanto | → Organizations and associations → Chemistry → Chemical technology |
| IUT | Internacia Unio pri Telekomunikado = ITU | International Telecommunication Union | In English = UIT | Union Internationale des Télécommunications | In French |
In Esperanto | → Organizations and associations → Telecommunications |
| JA | Juna Amiko | In Esperanto | |
| JA | Juna Alumeto | In Esperanto | → Newspapers, journalism |
| JAM | Junulara Azia Movado | In Esperanto | → Organizations and associations |
| JBLE | Japana Budhana Ligo Esperantista | In Esperanto | → Organizations and associations → Buddhism |
| JD | Junulara Delegito | In Esperanto | → 05 |
| JEA | Junularo Esperantista Apula | In Esperanto | → Organizations and associations |
| JEB | Junaj Esperantistoj en Britio (www.novajeb.org.uk) | In Esperanto | → Organizations and associations |
| JEB | Junularo Esperantista Brita (www.novajeb.org.uk) | In Esperanto | → Associations |
| JEFO | Junulara Esperantista Franca Organizo | In Esperanto | → Organizations and associations |
| JEI | Japana Esperanto-Instituto | In Esperanto | → Organizations and associations |
| JEJ | Japana Esperanto-Junularo = JEJ | 日本青年エスペラント連絡会 | In Japanese |
In Esperanto | → Organizations and associations |
| JEK | Junularo Esperantista Kanada | In Esperanto | → Organizations and associations |
| JELI | Junulara Esperanto-Ligo Israela | In Esperanto | → Organizations and associations |
| JER | Junulara Esperanta Renkontiĝo | In Esperanto | |
| JER | Jokohama Esperanto-Rondo | In Esperanto | |
| JES | Junularo Esperantista Svislanda (www.jesperanto.ch) | In Esperanto | → Associations |
| JK | Japana Kongreso | In Esperanto | → Congresses |
| JKEK | Justica Kortumo de Eŭropaj Kortumoj = CJEC | Court of Justice of the European Communities | In English = CJCE | Cour de Justice des Communautés Européennes | In French = TJCE | Tribunal de Justícia de les Comunitats Europees | In Catalan = LICE | Llys Cyfiawnder Ewrop | In Welsh = ΔΕΚ | Δικαστήριο των Ευρωπαϊκών Κοινοτήτων | In Greek = EuGH | Europäischer Gerichtshof | In German = TJCE | Tribunal de Justicia de las Comunidades Europeas | In Spanish = CGCE | Corte di Giustizia delle Comunità Europee | In Italian = HvJEG | Hof van Justitie van de Europese Gemeenschappen | In Dutch = EBTT | Europos Bendrijų Teisingumo Teismas | In Lithuanian |
In Esperanto | → Law, jurisprudence → European Union |
| JMA | Juna Membro-Abonanto | In Esperanto | → Organizations and associations → Newspapers, journalism |
| JMJ | Juna Membro kun Jarlibro | In Esperanto | → Organizations and associations |
| JOTE | Junulara Organizo de Togolandaj Esperantistoj | In Esperanto | → Organizations and associations |
| KAEM | Komisiono pri Azia Esperanto-Movado | In Esperanto | → Organizations and associations |
| KAEST | Konferenco pri Aplikoj de Esperanto en Scienco kaj Tekniko | In Esperanto | → Congresses → Mathematics and natural sciences → Applied sciences, technology |
| KAFE | Kultura Arta Festivalo en Esperanto | In Esperanto | → Civilization, culture, progress → Arts |
| KarEsA | Kartvelia Esperanto-Asocio | In Esperanto | → Associations |
| KBT | Komputada Baza Terminaro | In Esperanto | → Computer science → Dictionaries |
| KCE | Kultura Centro de Esperanto | In Esperanto | → Civilization, culture, progress |
| KD | Kompakta Disko = CD | Compact Disc | In English |
In Esperanto | → Music → Cinema, movies |
| KEA | Kataluna Esperanto-Asocio | In Esperanto | → Associations |
| KEA | Kanada Esperanto-Asocio | In Esperanto | → Associations |
| KEA | Kuba Esperanto-Asocio | In Esperanto | → Associations |
| KEILEU | Komitato por la Enkonduko de la Internacia Lingvo en Eŭropan Union | In Esperanto | → Organizations and associations → International relations → Language, linguistics, literature |
| KEJ | Korea Esperanto-Junularo | In Esperanto | → Organizations and associations |
| KEJ | Kataluna Esperanto-Junularo (www.esperanto.cat/kej/) | In Esperanto | → Organizations and associations |
| KEJA | Kroata Esperanto-Junulara Asocio (www.keja.hr) = HEM | Hrvatska Esperantska Mladež | In Croatian |
In Esperanto | → Associations |
| KEJO | Kebekia Esperantista Junulara Organizo | In Esperanto | → Organizations and associations |
| KEK | Konversacia Esperantista Klubo Kopenhago = KEK | Københavns Esperanto-Klub | In Danish |
In Esperanto | → Organizations and associations |
| KEKG | Kopenhaga Esperanto-Kulturgrupo = KEKG | Københavns Esperanto-Kulturgruppe | In Danish |
In Esperanto | → Organizations and associations → Civilization, culture, progress |
| KELI | Kristana Esperantista Ligo Internacia | In Esperanto | → Organizations and associations → Christianity |
| KER | Konga Esperanto-Rondo | In Esperanto | → Organizations and associations |
| KEV | Konciza Etimologia Vortaro | In Esperanto | → Dictionaries → Artificial languages (linguistics) |
| KIK | Konstanta Internacia Kvalifikejo | In Esperanto | → Education |
| KKES | Kvakera Esperanto-Servo | In Esperanto | → Christianity |
| KKKK | Komunik-kibernetikaj kernkursoj | In Esperanto | → Education |
| KKS | Konstanta Kongresa Sekretario | In Esperanto | → Organizations and associations |
| KKV | Kvinlingva Komputilteĥnika Vortaro | In Esperanto | → Computer science → Dictionaries |
| KL | Komputika Leksikono | In Esperanto | → Computer science → Dictionaries |
| KPSU | Komunisma Partio de Soveta Unio = PCUS | Parti Communiste de l'Union Soviétique | In French = SKUS | Strollad Komunour an Unaniezh Soviedel | In Breton = KPdSU | Kommunistische Partei der Sowjetunion | In German = KПCC | Коммунистическая партия Советского Союза | In Russian = KПCC | Kommunistitscheskaja Partija Sowjetskogo Sojusa | In Russian = KSSR | Komunistická strana Sovětského svazu | In Czech = PCUS | Partito Comunista dell'Unione Sovietica | In Italian = KPSU | Komunisma Partio de Soveta Unio | In Esperanto |
In Esperanto | → Political parties and movements |
| KPSU | Komunisma Partio de Soveta Unio = PCUS, SKUS, KPdSU, KПCC, KSSR (look above) |
In Esperanto | → Political parties and movements |
| KREA | Kostarika Esperanto-Asocio | In Esperanto | → Associations |
| KREH | Konsilio de Reciproka Ekonomia Helpo = СЭВ | Совет экономической взаимопомощи | In Russian = CAEM | Conseil d'Assistance Économique Mutuelle | In French = СИВ | Съвет за икономическа взаимопомощ | In Bulgarian = CAEM | Consell d'Assistència Econòmica Mútua | In Catalan = COMECON | Council of Mutual Economic Assistance | In English = RGW | Rat für gegenseitige Wirtschaftshilfe | In German = CAME | Consejo de Ayuda Mutua Económica | In Spanish = KGST | Kölcsönös Gazdasági Segítség Tanácsa | In Hungarian = SEV | Sovet Ekonomitšeskoi Vzaimopomoštši | In Russian = KNER | Këshilli i Ndihmës Ekonomike Reciproke | In Albanian = RVHP | Rada vzájemné hospodářské pomoci | In Czech = RWPG | Rada Wzajemnej Pomocy Gospodarczej | In Polish = CAER | Consiliul de Ajutor Economic Reciproc | In Romanian = RVHP | Rada vzájomnej hospodárskej pomoci | In Slovak = HĐTTKT | Hội đồng Tương trợ kinh tế | In Vietnamese = РЕВ | Рада Економічної Взаємодопомоги | In Ukrainian |
In Esperanto | → International relations → Economics |
| KS | Komuna Seminario | In Esperanto | → Congresses |
| KSM | Koresponda Servo Mondskala | In Esperanto | |
| KuN | Klavar-unuiĝo Nederlanda | In Esperanto | → Organizations and associations → Music |
| KUNKD | Konferenco de la Unuiĝintaj Nacioj pri Komerco kaj Disvolvado (www.unctad.org) = CNUCED | Conférence des Nations Unies sur le Commerce et le Développement | In French = UNCTAD | United Nations Conference on Trade and Development | In English = ЮНКТАД | Конференция на ООН за търговия и развитие | In Bulgarian = CNUCYD | Conferencia de las Naciones Unidas sobre Comercio y Desarrollo | In Spanish = UNCTAD | გაეროს ვაჭრობისა და განვითარების კონფერენცია | In Georgian = UNCTAD | การประชุมสหประชาชาติว่าด้วยการค้าและการพัฒนา | In Thai = UNCTAD | 聯合國貿易及發展委員會 | In Chinese = ICTR | International Criminal Tribunal for Rwanda | In English = TPIR | Tribunal Penal Internacional para Ruanda | In Spanish = TPIR | Tribunal Pénal International pour le Rwanda | In French = MTKR | Międzynarodowy Trybunał Karny dla Rwandy | In Polish = MTTR | Medzinárodný Trestný Tribunál pre Rwandu | In Slovak |
In Esperanto | → United Nations → Trade → Development |
| L | Leŭcino = L | Leucine | In English = L | Leucina | In Catalan = L | Leucin | In Danish = L | Leucin | In German = L | Leucina | In Spanish = L | Leucine | In French = L | 류신 | In Korean = L | Leucin | In Croatian = L | Leusin | In Indonesian = L | Leucina | In Italian = L | לאוצין | In Hebrew = L | Leicīns | In Latvian = L | Leucin | In Letzeburgesh = L | Leucinas | In Lithuanian = L | Leucine | In Dutch = L | ロイシン | In Japanese = L | Leucin | In Norwegian = L | Leucyna | In Polish = L | Leucina | In Portuguese = L | Лейцин | In Russian = L | Leusiini | In Finnish = L | Leucin | In Swedish = L | Lösin | In Turkish = L | Лейцин | In Ukrainian = L | 亮氨酸 | In Chinese |
In Esperanto | → Biochemistry, biophysics |
| LA | Landa Asocio | In Esperanto | → Associations |
| LASER | Lum-Amplifo per Stimulata Eligo de Radioj | In Esperanto | → Electromagnetism |
| LB | Londona Biblio | In Esperanto | → Christianity |
| LD | Lumdisko | In Esperanto | → Music → Cinema, movies |
| LEJL | Litovia Esperantista Junulara Ligo | In Esperanto | → Organizations and associations |
| LEJL | Litova Esperantista Junulara Ligo | In Esperanto | → Organizations and associations |
| LES | Lucerna Esperanto-Societo | In Esperanto | → Organizations and associations |
| LEUKAIS | Libera Eŭropia Universitato Kelemantia de AIS (Akademio Internacia de la Sciencoj) | In Esperanto | → Higher education, universities |
| LG | La Gazeto | In Esperanto | → Newspapers, journalism |
| Li | Litio = Li | Litium | In Afrikaans = Li | ليثيوم | In Arabic = Li | Litiu | In Asturian = Li | Літый | In Belarusian = Li | Литий | In Bulgarian = Li | লিথিয়াম | In Bengali = Li | Litijum | In Bosnian = Li | Liti | In Catalan = Li | Litiu | In Corsican = Li | Lithium | In Czech = Li | Лити | In Chuvash = Li | Lithiwm | In Welsh = Li | Lithium | In Danish = Li | Lithium | In German = Li | Λίθιο | In Greek = Li | Lithium | In English = Li | Litio | In Spanish = Li | Liitium | In Estonian = Li | Litio | In Basque = Li | لیتیوم | In Persian = Li | Litium | In Finnish = Li | Liti | In Friulian = Li | Litiam | In Irish = Li | Litio | In Galician = Li | ליתיום | In Hebrew = Li | लिथियम | In Hindi = Li | Litij | In Croatian = Li | Lityòm | HT = Li | Lítium | In Hungarian = Li | Լիթիում | In Armenian = Li | Litium | In Indonesian = Li | Litio | In Ido = Li | Litín | In Icelandic = Li | Litio | In Italian = Li | リチウム | In Japanese = Li | roksodna | JBO = Li | ლითიუმი | In Georgian = Li | 리튬 | In Korean = Li | Lithium | KSH = Li | Lîtyûm | In Kurdish = Li | Lithium | In Latin = Li | Lithium | In Letzeburgesh = Li | Litis | In Lithuanian = Li | Litijs | In Latvian = Li | Литиум | In Macedonian = Li | ലിഥിയം | In Malayalam = Li | Litium | In Malay = Li | Lithium | NDS = Li | Lithium | In Dutch = Li | Litium | In Nynorsk = Li | Litium | In Norwegian = Li | Liti | In Occitan = Li | Lit | In Polish = Li | Lítio | In Portuguese = Li | Lityu | In Quechua = Li | Litiu | In Romanian = Li | Литий | In Russian = Li | लिथियम | In Sanskrit = Li | Litij | In Serbo-Croatian = Li | Lítium | In Slovak = Li | Litij | In Slovenian = Li | Litiumi | SQ = Li | Литијум | In Serbian = Li | Litium | In Swedish = Li | Lithi | In Swahili = Li | லித்தியம் | In Tamil = Li | ลิเทียม | In Thai = Li | Lityum | In Turkish = Li | Літій | In Ukrainian = Li | Litiy | In Uzbek = Li | Liti | In Vietnamese = Li | Litiom | In Walloon = Li | ליטיום | In Yiddisch = Li | 锂 | In Chinese |
In Esperanto | → Chemistry |
| LI | Lingvo Internacia | In Esperanto | → Language, linguistics, literature |
| LIBE | Ligo Internacia de Blindaj Esperantistoj | In Esperanto | → Organizations and associations |
| LK | Lingva Komitato | In Esperanto | → Organizations and associations → Linguistics |
| LK | Lingva Komitatano | In Esperanto | → Linguistics |
| LKK | Loka Kongresa Komitato | In Esperanto | → Organizations and associations → Congresses |
| LLZ | Lazaro Ludoviko Zamenhof | In Esperanto | → Biography |
| LMLP | La Monda Lingvo-Problemo | In Esperanto | → Language, linguistics, literature |
| LOdE | La Ondo de Esperanto | In Esperanto | → Newspapers, journalism |
| LSG | Ligo de Samseksamaj Geesperantistoj | In Esperanto | → Collective works |
| M | Metionino = M | Methionine | In English = M | Metionina | In Catalan = M | Methionin | In German = M | Metionina | In Spanish = M | Méthionine | In French = M | 메티오닌 | In Korean = M | Metionin | In Indonesian = M | Metionina | In Italian = M | Metionin | In Croatian = M | מתיונין | In Hebrew = M | Metionīns | In Latvian = M | Methionin | In Letzeburgesh = M | Metioninas | In Lithuanian = M | Methionine | In Dutch = M | メチオニン | In Japanese = M | Metionin | In Norwegian = M | Metionina | In Polish = M | Metionina | In Portuguese = M | Метионин | In Russian = M | Метионин | In Serbian = M | Metioniini | In Finnish = M | Metionin | In Swedish = M | Metiyonin | In Turkish = M | Метіонін | In Ukrainian = M | 蛋氨酸 | In Chinese |
In Esperanto | → Biochemistry, biophysics |
| MA | Membro-Abonanto | In Esperanto | → Organizations and associations → Newspapers, journalism |
| MEKARO | MezKanada Renkontiĝo de Esperanto | In Esperanto | → Congresses |
| MEL | Muzika Esperanto Ligo | In Esperanto | → Organizations and associations → Music |
| MEM | Mondpaca Esperantista Movado | In Esperanto | → Organizations and associations → Politics |
| MEMO | Montreala Esperanta Movado = MEMO | Montreal Esperanto Movement | In English = MEMO | Mouvement Espéranto-Montréal | In French |
In Esperanto | → Organizations and associations |
| MEP | Malneta Enlanda Produkto = GDP | Gross Domestic Product | In English = BKT | Bruttokansantuote | In Finnish = PIB | Producte Interior Brut | In Catalan = PIL | Prodotto Interno Lordo | In Italian = BNO | Bruto Nationoal Product | VLS |
In Esperanto | → Economics |
| MJ | Membro kun Jarlibro | In Esperanto | → Organizations and associations |
| MKO | Monda Komerca Organizaĵo = MOK | Monda Organiz(aĵ)o pri Komerco | In Esperanto = WTO | World Trade Organization | In English = OMC | Organisation Mondiale du Commerce | In French |
In Esperanto | → International relations → Trade |
| MKR | MontKabana Renkontiĝo | In Esperanto | → Congresses |
| MMO | Monda Meteologia Organizo = WMO | World Meteriological Organization | In English = OMM | Organisation Météorologique Mondiale | In French |
In Esperanto | → International relations → Meteorology, climatology |
| Mn | Mangano = Mn | Manganese | In French = Mn | Mangaan | In Estonian = Mn | منجنيز | In Arabic = Mn | Manqan | In Azerbaijani = Mn | Mangan | In German = Mn | Манган | In Bulgarian = Mn | Manganès | In Friulian = Mn | Μαγγάνιο | In Greek = Mn | Manganeso | In Spanish = Mn | منگنز | In Persian = Mn | Manganese | In English = Mn | Mangaan | In Afrikaans = Mn | Mangan | In Bosnian = Mn | Manganès | In Catalan = Mn | Mangan | In Danish |
In Esperanto | → Chemistry |
| MNP | Malneta Nacia Produkto = BNP | Bruto Nasionale Produk | In Afrikaans |
In Esperanto | → Economics |
| MOIP | Monda Organizo pri Intelekta Proprieto (www.wipo.int) = WIPO | World Intellectual Property Organisation | In English = WIPO | World Intellectual Property Organization | In English = OMPI | Organisation Mondiale de la Propriété Intellectuelle | In French = OMPI | Organizaţia Mondială a Proprietăţii Intelectuale | In Romanian |
In Esperanto | → International relations → Industrial property → Artistic property |
| MOK | Monda Organiz(aĵ)o pri Komerco = MKO, WTO, OMC (look above) |
In Esperanto | → International relations → Trade |
| MOS | Monda Organiz(aĵ)o pri Sano = WHO | World Health Organization | In English = OMS | Organisation Mondiale de la Santé | In Esperanto = OMS | Organizzazione Mondiale della Sanità | In Italian = WGO | Wêreldgesondheidsorganisasie | In Afrikaans = OMS | Organización Mundial de la Salú | In Asturian = СЗО | Световната здравна огранизация | In Bulgarian = SZO | Světová zdravotnická organizace | In Czech = OMS | Organització Mundial de la Salut | In Catalan = OMS | Organización Mundial de la Salud | In Spanish = MTO | Maailma Terviseorganisatsioon | In Estonian = MOE | Munduko Osasun Erakundea | In Basque = OMS | Organisacion mondiâla de la sandât | FRP = OMS | Organización Mundial da Saúde | In Galician = SZO | Svjetska zdravstvena organizacija | In Croatian = RTD | Rêxistina Tendurustiyê ya Dinyayê | In Kurdish = UMS | Urganizazziun mundiala da la Santaa | In Lombard = PSO | Pasaulio sveikatos organizacija | In Lithuanian = PVO | Pasaules veselības organizācija | In Latvian |
In Esperanto | → United Nations → Medicine |
| MS | Membro-Subtenanto | In Esperanto | → Organizations and associations |
| MSZ | Membro de Societo Zamenhof | In Esperanto | → Organizations and associations |
| MT | Monda Turismo | In Esperanto | → Organizations and associations → Tourism |
| N | Asparagino = N | Asparagine | In English = N | Asparagina | In Catalan = N | Asparagin | In German = N | Asparagina | In Spanish = N | Asparagine | In French = N | 아스파라긴 | In Japanese = N | Asparagin | In Indonesian = N | Asparagina | In Italian = N | אספרגין | In Hebrew = N | Asparagīns | In Latvian = N | Asparagin | In Letzeburgesh = N | Asparaginas | In Lithuanian = N | Asparagine | In Dutch = N | アスパラギン | In Japanese = N | Asparagina | In Polish = N | Asparagina | In Portuguese = N | Аспарагин | In Russian = N | Asparagín | In Slovak = N | Аспарагин | In Serbian = N | Asparagiini | In Finnish = N | Asparagin | In Swedish = N | Asparagin | In Turkish = N | Аспарагін | In Ukrainian = N | 天冬酰胺 | In Chinese |
In Esperanto | → Biochemistry, biophysics |
| N | Azoto = N | Azote | In French = N | Stikstof | In Afrikaans = N | نيتروجين | In Arabic = N | Nitróxenu | In Asturian = N | Azot | In Azerbaijani = N | Азот | In Belarusian = N | Азот | In Bulgarian = N | নাইট্রোজেন | In Bengali = N | Dušik | In Bosnian = N | Nitrogen | In Catalan = N | Azotu | In Corsican = N | Dusík | In Czech = N | Азот | In Chuvash = N | Nitrogen | In Welsh = N | Kvælstof | In Danish = N | Stickstoff | In German = N | Άζωτο | In Greek = N | Nitrogen | In English = N | Nitrógeno | In Spanish = N | Lämmastik | In Estonian = N | Nitrogeno | In Basque = N | نیتروژن | In Persian = N | Typpi | In Finnish = N | Azôt | In Friulian = N | Nítrigin | In Irish = N | Nitróxeno | In Galician = N | નાઇટ્રોજન | GU = N | Neetragien | GV = N | חנקן | In Hebrew = N | नाइट्रोजन | In Hindi = N | Dušik | In Croatian = N | Azòt | HT = N | Nitrogén | In Hungarian = N | Ազոտ | In Armenian = N | Nitrogeno | In Interlingua = N | Nitrogen | In Indonesian = N | Nitro | In Ido = N | Nitur | In Icelandic = N | Azoto | In Italian = N | 窒素 | In Japanese = N | trano | JBO = N | აზოტი | In Georgian = N | 질소 | In Korean = N | Stickstoff | KSH = N | Nîtrojen | In Kurdish = N | Nitrogenium | In Latin = N | Stéckstoff | In Letzeburgesh = N | Stikstof | LI = N | Azoti | In Lingala = N | Azotas | In Lithuanian = N | Slāpeklis | In Latvian = N | Hauota | In Māori = N | Азот | In Macedonian = N | നൈട്രജന് | In Malayalam = N | Азот | In Mongolian = N | नायट्रोजन | MR = N | Ehēcatehuiltic | En Nahuatl = N | Stickstoff | NDS = N | Stikstof | In Dutch = N | Nitrogen | In Nynorsk = N | Nitrogen | In Norwegian = N | Nitrogene | NOV = N | Azòt | In Occitan = N | Nitrogen | PAM = N | Azot | In Polish = N | Nitrogénio | In Portuguese = N | Qullpachaq | In Quechua = N | Azot | In Romanian = N | Азот | In Russian = N | Azzotu | In Sicilian = N | Dušik | In Serbo-Croatian = N | Dusík | In Slovak = N | Dušik | In Slovenian = N | Azoti | SQ = N | Азот | In Serbian = N | Kväve | In Swedish = N | Nitrojeni | In Swahili = N | நைட்ரஜன் | In Tamil = N | నత్రజని | TE = N | Азот | In Tajik = N | ไนโตรเจน | In Thai = N | Azot | In Turkish = N | Азот | In Ukrainian = N | Azot | In Uzbek = N | Nitơ | In Vietnamese = N | 氮 | In Chinese |
In Esperanto | → Chemistry |
| Na | Natrio = Na | Sodium | In French = Na | Natrium | In Afrikaans = Na | صوديوم | In Arabic = Na | Sodiu | In Asturian = Na | Натрый | In Belarusian = Na | Натрий | In Bulgarian = Na | সোডিয়াম | In Bengali = Na | Natrijum | In Bosnian = Na | Sodi | In Catalan = Na | Sodiu | In Corsican = Na | Sodík | In Czech = Na | Sodiwm | In Welsh = Na | Natrium | In Danish = Na | Natrium | In German = Na | ސޯޑިއަމް | DV = Na | Νάτριο | In Greek = Na | Sodium | In English = Na | Sodio | In Spanish = Na | Naatrium | In Estonian = Na | Sodio | In Basque = Na | سدیم | In Persian = Na | Natrium | In Finnish = Na | Sodi | In Friulian = Na | Sóidiam | In Irish = Na | Sodio | In Galician = Na | Sodjum | GV = Na | נתרן | In Hebrew = Na | सोडियम | In Hindi = Na | Natrij | In Croatian = Na | Sodyòm | HT = Na | Nátrium | In Hungarian = Na | Նատրիում | In Armenian = Na | Natrium | In Indonesian = Na | Natro | In Ido = Na | Natrín | In Icelandic = Na | Sodio | In Italian = Na | ナトリウム | In Japanese = Na | sodna | JBO = Na | Natrium | JV = Na | ნატრიუმი | In Georgian = Na | ಸೋಡಿಯಮ್ | KN = Na | 나트륨 | In Korean = Na | Natrîyûm | In Kurdish = Na | Natrium | In Latin = Na | Natrium | In Letzeburgesh = Na | Sodu | In Lingala = Na | Natris | In Lithuanian = Na | Nātrijs | In Latvian = Na | Konutai | In Māori = Na | Натриум | In Macedonian = Na | സോഡിയം | In Malayalam = Na | सोडियम | MR = Na | Natrium | NDS = Na | Natrium | In Dutch = Na | Natrium | In Nynorsk = Na | Natrium | In Norwegian = Na | Natrium | NOV = Na | Sôdgium | In Norman = Na | Sòdi | In Occitan = Na | Sód | In Polish = Na | Sódio | In Portuguese = Na | Natriyu | In Quechua = Na | Sodiu | In Romanian = Na | Натрий | In Russian = Na | Sodiu | In Sicilian = Na | Natrij | In Serbo-Croatian = Na | Sodík | In Slovak = Na | Natrij | In Slovenian = Na | Natriumi | SQ = Na | Натријум | In Serbian = Na | Natrium | In Swedish = Na | Natiri | In Swahili = Na | சோடியம் | In Tamil = Na | సోడియమ్ | TE = Na | Натрий | In Tajik = Na | โซเดียม | In Thai = Na | Sodyum | In Turkish = Na | Натрій | In Ukrainian = Na | Natriy | In Uzbek = Na | Natri | In Vietnamese = Na | Sodiom | In Walloon = Na | 钠 | In Chinese |
In Esperanto | → Chemistry |
| NASK | Nord-Amerika Somera Kursaro | In Esperanto | → Education |
| NATO | Nord-Atlantika Traktat-Organizo (www.nato.int) = OTAN | Organització del Tractat de l'Atlàntic Nord | In Catalan = NATO | North Atlantic Treaty Organisation | In English = OTAN | Organizazión d'o Tratau de l'Atlantico Norte | In Aragonese = OTAN | Organización del Tratáu del Atlánticu Norte | In Asturian = AFNA | Aozadur Feur-emglev Norzh-Atlantel | In Breton = OTAN | Organisation du Traité de l'Atlantique Nord | In French = ন্যাটো | উত্তর আটলান্টিক নিরাপত্তা জোট | In Bengali = NATO | Οργανισμός Βορειοατλαντικού Συμφώνου | In Greek = NATO | Nordatlantikvertrag-Organisation | In German = OTAN | Organización del Tratado del Atlántico Norte | In Spanish = NAFO | Noard-Atlantyske Ferdrachsorganisaasje | In Frisian = OTAN | Organización do Tratado do Atlántico Norte | In Galician = ნატო | ჩრდილოატლანტიკური თანამშრომლობის ორგანიზაცია | In Georgian = OTAN | Organização do Tratado do Atlântico Norte | In Portuguese = OTNA | Organizaciya le Tratatosko le Nordutne Atlantikosko | In Vlax Romani = OTAN | Organizaţia Tratatului Atlanticului de Nord | In Romanian = NATO | Organisatschoon vun den Noordatlantikverdrag | NDS |
In Esperanto | → International relations |
| NBN | (Asocio por la enkonduko de) Nova Biologia Nomenklaturo | In Esperanto | → Associations → Biological sciences |
| NEIGHBOUR | Nova Eduka Iniciato Garantianta Heterogenecon kaj Bilingvismon, Observanta Universalajn Regulojn | In Esperanto | → Education |
| NEJ | Nederlanda Esperanta Junularo (www.esperanto-jongeren.nl) = NEJ | Nederlandse Esperantojongeren | In Dutch |
In Esperanto | → Organizations and associations |
| NEK | Nordjutlanda Esperanto-Klubo = NEK | Nordjyllands Esperanto-Klub | In Danish |
In Esperanto | → Organizations and associations |
| NEL | Norvega Esperantista Ligo (www.esperanto.no) | In Esperanto | → Organizations and associations |
| NHA | Nova Help-Alfabeto | In Esperanto | → Writing systems |
| NIFO | Neidentigita Fluganta Objekto = OVNI | Objet Volant Non Identifié | In French = OVNI | Objecte Volador No Identificat | In Catalan = НЛО | Неидентифициран летящ обект | In Bulgarian = OVNI | Objeto Volador No Identificado | In Spanish = UFO | Unidentifiziertes Flugobjekt | In German = UFO | Unidentified Flying Object | In English = UFO | Unknown Flying Object | In English = UFO | Uidentificeret flyvende objekt | In Danish = UFO | Unbekend fleanend objekt | In Frisian = עב"מ | עצם בלתי מזוהה | In Hebrew = OVNI | Oggetto Volante Non Identificato | In Italian = NLO | Neidentificēts lidojošs objekts | In Latvian = UFO | Uidentifisert flygende objekt | In Norwegian = UFO | Uidentifisert flygande objekt | In Nynorsk = NOL | Niezidentyfikowany Obiekt Latający | In Polish = OVNI | Objeto Voador Não Identificado | In Portuguese = OZN | Obiect Zburător Neidentificat | In Romanian = НЛО | Неопознанный летающий объект | In Russian = NLO | Neidentifikovani leteći objekat | In Serbo-Croatian |
In Esperanto | → Spaceflight engineering, astronautics |
| NJE | Norvega Junularo Esperantista | In Esperanto | → Organizations and associations |
| NOGESO | NOrda Grupo de Esperanto-StudadO | In Esperanto | → Organizations and associations |
| NPIV | Nova Plena Ilustrita Vortaro | In Esperanto | → Dictionaries → Artificial languages (linguistics) |
| NR | Novjara Renkontiĵo | In Esperanto | |
| NRO | Ne-Registara Organizo = ONGs | Organizações Não Governamentais | In Portuguese = NGO | Non-Governmental Organization | In English = NGO | Nichtregierungsorganisation | In German = ANG | Aozadur Nann-Gouarnamantel | In Breton = ONG | Organisation Non Gouvernementale | In French = ONG | Organizzazione non governativa | In Italian = LSM | Lembaga Swadaya Masyarakat | In Indonesian = ONG | Organización non gobernamental | In Galician = GKE | Gobernuz Kanpoko Erakunde | In Basque = ONG | Organización no gubernamental | In Spanish = ΜΚΟ | Μη κυβερνητικές οργανώσεις | In Greek = NNO | Nevládní nezisková organizace | In Czech = ONG | Organització no governamental | In Catalan = ННО | Неурядові неприбуткові організації | In Ukrainian = ONG | Organização não governamental | In Portuguese = NGO | Niet-gouvernementele organisatie | In Dutch = NVO | Nevyriausybinė organizacija | In Lithuanian |
In Esperanto | → Organizations and associations |
| NRO | Neregistara Organizajo | In Esperanto | → Organizations and associations |
| O | Oksigeno = O | Oxygène | In French = O | Suurstof | In Afrikaans = O | Sauerstoff | ALS = O | أكسجين | In Arabic = O | Oxíxenu | In Asturian = O | Oksigen | In Azerbaijani = O | Sauastoff | BAR = O | Кісларод | In Belarusian = O | Кислород | In Bulgarian = O | অক্সিজেন | In Bengali = O | Oksigen | In Breton = O | Kiseonik | In Bosnian = O | Oxigen | In Catalan = O | Ossigenu | In Corsican = O | Kyslík | In Czech = O | Йӳçлĕк | In Chuvash = O | Ocsigen | In Welsh = O | Ilt | In Danish = O | Sauerstoff | In German = O | Οξυγόνο | In Greek = O | Oxygen | In English = O | Oxígeno | In Spanish = O | Hapnik | In Estonian = O | Oxigeno | In Basque = O | اکسیژن | In Persian = O | Happi | In Finnish = O | Ossigjen | In Friulian = O | Soerstof | In Frisian = O | Ocsaigin | In Irish = O | Àile-beatha | GD = O | Osíxeno | In Galician = O | ઑક્સીજન | GU = O | Ocsygien | GV = O | חמצן | In Hebrew = O | आक्सीजन | In Hindi = O | Kisik | In Croatian = O | Kislik | HSB = O | Oksijèn | HT = O | Oxigén | In Hungarian = O | Թթվածին | In Armenian = O | Oxygeno | In Interlingua = O | Oksigen | In Indonesian = O | Oxo | In Ido = O | Súrefni | In Icelandic = O | Ossigeno | In Italian = O | 酸素 | In Japanese = O | kijno | JBO = O | Oksigen | JV = O | ჟანგბადი | In Georgian = O | ಆಮ್ಲಜನಕ | KN = O | 산소 | In Korean = O | Sauerstoff | KSH = O | Oksîjen | In Kurdish = O | Oxygenium | In Latin = O | Sauerstoff | In Letzeburgesh = O | Zuurstof | LI = O | Oksijɛ́ní | In Lingala = O | Deguonis | In Lithuanian = O | Skābeklis | In Latvian = O | Hāora | In Māori = O | Кислород | In Macedonian = O | ഓക്സിജന് | In Malayalam = O | Хүчилтөрөгч | In Mongolian = O | ऑक्सिजन | MR = O | Oksigen | In Malay = O | Ehēcayoh | En Nahuatl = O | Suerstoff | NDS = O | अक्सिजन | NEW = O | Zuurstof | In Dutch = O | Oksygen | In Nynorsk = O | Oksygen | In Norwegian = O | Oxygen | OM = O | Oxygen | PAM = O | Tlen | In Polish = O | Oxigénio | In Portuguese = O | Muksichaq | In Quechua = O | Oxigen | In Romanian = O | Кислород | In Russian = O | Ossìgginu | In Sicilian = O | Kiseonik | In Serbo-Croatian = O | ඔක්සිජන් | SI = O | Kyslík | In Slovak = O | Kisik | In Slovenian = O | Oksigjeni | SQ = O | Кисеоник | In Serbian = O | Oksigén | SU = O | Syre | In Swedish = O | Oksijeni | In Swahili = O | ஆக்ஸிஜன் | In Tamil = O | ఆక్సిజన్ | TE = O | Оксиген | In Tajik = O | ออกซิเจน | In Thai = O | Oksiheno | In Tagalog = O | Oksijen | In Turkish = O | Кисень | In Ukrainian = O | Kislorod | In Uzbek = O | Ôxy | In Vietnamese = O | זויערשטאף | In Yiddisch = O | 氧 | In Chinese |
In Esperanto | → Chemistry |
| OEKE | Organizaĵo por Ekonomiaj Kunlaboro kaj Evoluigo | In Esperanto | → Organizations and associations → Economics |
| OEKE | Organizaĵo pri Ekonomiaj Kunlaboro kaj Evoluigo (www.oecd.org) = OECD | Organisation for Economic Cooperation and Development | In English = OCDE | Organisation de Coopération et de Développement Économique | In French = OCDE | Organizaţia de Cooperare şi Dezvoltare Economică | In Romanian = ΟΟΣΑ | Οργανισμός Οικονομικής Συνεργασίας και Ανάπτυξης | In Greek = OESO | Organisasie vir Ekonomiese Samewerking en Ontwikkeling | In Afrikaans = OCDE | Organització per a la Cooperació i el Desenvolupament Econòmic | In Catalan = ОИСР | Организация за икономическо сътрудничество и развитие | In Bulgarian = OECD | منظمة التعاون والتنمية الاقتصادية | In Arabic = OESO | Organisatie voor Economische Samenwerking en Ontwikkeling | In Dutch = OCDE | Organización para la Cooperación y el Desarrollo Económico | In Spanish = KHEE | Kooperazio eta Hazkunde Ekonomikorako Erakundea | In Basque = OCDE | Organisation de cooperation e de developament economic | In Interlingue = OECD | 경제 협력 개발 기구 | In Korean = OECD | 経済協力開発機構 | In Japanese = OCSE | Organizzazione per la Cooperazione e lo Sviluppo Economico | In Italian = OECD | 经济合作与发展组织 | In Chinese = OECD | Tổ chức Hợp tác và Phát triển Kinh tế | In Vietnamese = OECD | องค์การเพื่อความร่วมมือทางเศรษฐกิจและการพัฒนา | In Thai = ОЭСР | Организация экономического сотрудничества и развития | In Russian = OCDE | Organização para a Cooperação e Desenvolvimento Económico | In Portuguese |
In Esperanto | → International relations → International economic cooperation |
| OkSEJT | Okcidenta Somera Junulara Tendaro | In Esperanto | |
| OKUNHK | Oficejo de la Kunordiganto de la Unuiĝintaj Nacioj por Helpo kaze de Katastrofo = UNDRO | Office of the United Nations Desaster Relief Coordinator | In English |
In Esperanto | → United Nations → Natural disasters |
| OLP | Organizaĵo por Liberigo de Palestino = PLO | Palestine Liberation Organization | In English = FAT | Fələstin Azadlıq Təşkilatı | In Azerbaijani = ООП | Организация за освобождение на Палестина | In Bulgarian = OAP | Organització per a l'Alliberament de Palestina | In Catalan = OOP | Organizace pro osvobození Palestiny | In Czech = OLP | Organización para la Liberación de Palestina | In Spanish = OLP | Organisation de Libération de la Palestine | In French = PAE | Palestinaren Askapenerako Erakundea | In Basque = OLP | Organización para a Liberación da Palestina | In Galician = PLO | 팔레스타인 해방기구 | In Korean = OLP | Organização para a Libertação da Palestina | In Portuguese = OWP | Organizacja Wyzwolenia Palestyny | In Polish = PLO | パレスチナ解放機構 | In Japanese = ПЛО | Палестинската ослободителна организација | In Macedonian = PIO | Palestinos išsivadavimo organizacija | In Lithuanian = პგო | პალესტინის განთავისუფლების ორგანიზაცია | In Georgian = OLP | Organizzazione per la Liberazione della Palestina | In Italian = ООП | Организация освобождения Палестины | In Russian = ПЛО | Палестинска ослободилачка организација | In Serbian = PLO | 巴勒斯坦解放組織 | In Chinese = OВП | Організація визволення Палестини | In Ukrainian = FKÖ | Filistin Kurtuluş Örgütü | In Turkish |
In Esperanto | → Political parties and movements |
| OMS | Organisation Mondiale de la Santé = MOS, WHO, WGO, СЗО, SZO, MTO, MOE, RTD, UMS, PSO, PVO (look above) |
In Esperanto | → United Nations → Medicine |
| ONA | Organizo por Nutrado kaj Agrikulturo = FAO | Food and Agriculture Organization | In English |
In Esperanto | → International relations → Agricultural sciences → Food technology |
| OPEL | Organizaĵo de Petrol-Eksportaj Landoj = OPEC | Organization of the Petroleum Exporting Countries | In English = OPEP | Organisation des Pays Exportateurs de Pétrole | In French = OPEC | Organization of Petroleum Exporting Countries | In English = OPEP | Organização dos Países Exportadores de Petróleo | In Portuguese = OPEP | Organización de Países Esportadores de Petroleu | In Asturian = OPEP | Organización de Países Exportadores de Petróleo | In Spanish = OPEP | Organització de Països Exportadors de Petroli | In Catalan = ОПЕК | Организација на земји извознички на нафта и нафтени деривати | In Macedonian |
In Esperanto | → Organizations and associations → Mining → 665 |
| OSIEK | Organiza Societo de Internaciaj Esperanto-Konferencoj | In Esperanto | → Organizations and associations → Congresses |
| OSR | Optika signorekono | In Esperanto | |
| OUNID | Organizo de la Unuiĝintaj Nacioj por Industria Disvolvado (www.unido.org) = UNIDO | United Nations Industrial Development Organization | In English |
In Esperanto | → International relations → Industry, industrial policy → United Nations |
| P | Fósforo = P | Fosfor | In Dutch = P | Phosphor | In German = P | Phosphore | In French = P | Phosphorus | In English |
In Esperanto | → Chemistry |
| P | Prolino = P | Proline | In English = P | প্রোলিন | In Bengali = P | Prolina | In Catalan = P | Prolin | In Danish = P | Prolin | In German = P | Prolina | In Spanish = P | Proline | In French = P | 프롤린 | In Korean = P | Prolin | In Croatian = P | Prolin | In Indonesian = P | Prolina | In Italian = P | פרולין | In Hebrew = P | Prolīns | In Latvian = P | Prolin | In Letzeburgesh = P | Prolinas | In Lithuanian = P | Prolin | In Hungarian = P | Proline | In Dutch = P | プロリン | In Japanese = P | Prolina | In Polish = P | Prolina | In Portuguese = P | Пролин | In Russian = P | Proliini | In Finnish = P | Prolin | In Swedish = P | Prolin | In Turkish = P | Пролін | In Ukrainian = P | 脯氨酸 | In Chinese |
In Esperanto | → Biochemistry, biophysics |
| PAG | Plena Analiza Gramatiko | In Esperanto | → Linguistics |
| PakEsA | Pakistana Esperanto-Asocio | In Esperanto | → Associations |
| PEJ | Portugala Esperanto-Junularo | In Esperanto | → Associations |
| PEJ | Pola Esperanto-Junularo | In Esperanto | → Organizations and associations |
| PEK | Perfektiga Esperanto-Kurso | In Esperanto | → Education → Artificial languages (linguistics) |
| PEM | Por-Esperanta Mormonaro | In Esperanto | → Organizations and associations → Christianity |
| PG | Plena Gramatiko | In Esperanto | → Linguistics |
| PIF | Pupteatra Internacia Festivalo | In Esperanto | → Entertainment |
| PIV | Plena Ilustrita Vortaro | In Esperanto | → Dictionaries → Artificial languages (linguistics) |
| PK | Persona Komputilo | In Esperanto | → Hardware |
| PLA | Palestina Liberiga Armeo | In Esperanto | → 355 |
| PMEG | Plena Manlibro de Esperanta Gramatiko | In Esperanto | → Encyclopaedias, reference works → Artificial languages (linguistics) |
| POD | Plej Oftaj Demandoj = FAQ | Frequently Asked Questions | In English = FAQ | Foire Aux Questions | In French = SIL | Su'aalaha Intabadan La'isweydiiyey | In Somali |
In Esperanto | → Science and knowledge |
| PR | Printempa Renkontiĝo | In Esperanto | → Congresses |
| PSI | Printempa Semajno Internacia | In Esperanto | → Congresses |
| PTT | Poŝto, Telegrafo kaj Telefono | In Esperanto | → Telecommunications → Transport and postal services |
| PUND | Programo de la Unuiĝintaj Nacioj pri Disvolvado = PNUD | Programme des Nations Unies pour le Développement | In French = PNUD | Programa de les Naciones Uníes pa'l Desendolcu | In Asturian = PNUD | Programul Naţiunilor Unite pentru Dezvoltare | In Romanian = UNDP | United Nations Development Programme | In English = PNUD | Programa de las Naciones Unidas para el Desarrollo | In Spanish = PNUD | Programa de les Nacions Unides per al Desenvolupament | In Catalan = UNDP | გაეროს განვითარების პროგრამა | In Georgian = UNDP | জাতিসংঘ উন্নয়ন কর্মসূচী | In Bengali = PNUD | Programa das Nações Unidas para o Desenvolvimento | In Portuguese = ПРООН | Программа развития ООН | In Russian = UNDP | สำนักงานโครงการพัฒนาแห่งสหประชาชาติ | In Thai = UNDP | ஐக்கிய நாடுகள் வளர்ச்சித் திட்டம் | In Tamil = UNDP | 联合国开发计划署 | In Chinese |
In Esperanto | → International relations → Development → United Nations |
| PV | Plena Vortaro | In Esperanto | → Dictionaries → Artificial languages (linguistics) |
| Q | Glutamino = Q | Glutamine | In English = Q | Glutamina | In Catalan = Q | Glutamin | In Czech = Q | Glutamin | In German = Q | Glutamina | In Spanish = Q | Glutamine | In French = Q | 글루타민 | In Korean = Q | Glutamin | In Indonesian = Q | Glutammina | In Italian = Q | גלוטמין | In Hebrew = Q | Glutamīns | In Latvian = Q | Glutamin | In Letzeburgesh = Q | Glutaminas | In Lithuanian = Q | Glutamine | In Dutch = Q | グルタミン | In Japanese = Q | Glutamina | In Polish = Q | Glutamina | In Portuguese = Q | Глутамин | In Russian = Q | Glutamín | In Slovak = Q | Глутамин | In Serbian = Q | Glutamiini | In Finnish = Q | Glutamin | In Swedish = Q | Glutamin | In Turkish = Q | Глутамін | In Ukrainian = Q | 穀氨醯胺 | In Chinese |
In Esperanto | → Biochemistry, biophysics |
| R | Arginino = R | Arginine | In English = R | Arginina | In Catalan = R | Arginin | In Czech = R | Arginin | In German = R | Arginina | In Spanish = R | Arginine | In French = R | 아르기닌 | In Korean = R | Arginin | In Croatian = R | Arginin | In Indonesian = R | Arginina | In Italian = R | ארגינין | In Hebrew = R | Arginīns | In Latvian = R | Arginin | In Letzeburgesh = R | Argininas | In Lithuanian = R | Arginine | In Dutch = R | アルギニン | In Japanese = R | آرګېنين | In Pashto = R | Arginina | In Polish = R | Arginina | In Portuguese = R | Аргинин | In Russian = R | Arginín | In Slovak = R | Arginiini | In Finnish = R | Arginin | In Swedish = R | Arginin | In Turkish = R | Аргінін | In Ukrainian = R | 精氨酸 | In Chinese |
In Esperanto | → Biochemistry, biophysics |
| RADE | Rotaria Amikaro de Esperantistoj | In Esperanto | → Organizations and associations |
| REJM | Rusia Esperantista Junulara Movado | In Esperanto | → Organizations and associations |
| REU | Rusia Esperantista Unio (www.reu.ru) | In Esperanto | → Organizations and associations |
| REVI | Rondo de Esperantistaj Verserĉantoj per Interreto | In Esperanto | → Organizations and associations → Literature |
| RIC | Reta Informado-Centro | In Esperanto | → Libraries → Networks, communication |
| RNA | Ribonuklea acido = ARN | Acidum ribonucleinicum | In Latin = RNA | Ribonucleic acid | In English = ARN | Acide ribonucléique | In French = РНК | Рибонуклеинова киселина | In Russian = ARN | حمض ريبي نووي | In Arabic = TRN | Trenkenn ribonukleek | In Breton = ARN | Àcid ribonucleic | In Catalan = RNK | Ribonukleová kyselina | In Czech = RNS | Ribonukleinsäure | In German = ARN | Azido erribonukleiko | In Basque = ARN | Ácido ribonucleico | In Spanish = RNH | Ribonukleiinhape | In Estonian = RKS | Ríbósakjarnasýru | In Icelandic |
In Esperanto | → Genetics → Biochemistry, biophysics |
| RO | Revuo Orienta | In Esperanto | → Serial publications, periodicals |
| RSM | Respubliko de San Marino | In Esperanto | → Geography |
| RTA | Radioteknika Artikolaro | In Esperanto | → Telecommunications |
| RTG | Radioiziotopa Termoelektra Generatoro | In Esperanto | → Nuclear technology |
| RumEJA | Rumana Esperantista Junulara Asocio | In Esperanto | → Associations |
| S | Sulfuro = S | Soufre | In French = S | Swawel | In Afrikaans = S | كبريت | In Arabic = S | Azufre | In Asturian = S | Kükürd | In Azerbaijani = S | Сера | In Belarusian = S | Сяра | In Bulgarian = S | গন্ধক | In Bengali = S | Sumpor | In Bosnian = S | Sofre | In Catalan = S | Zolfu | In Corsican = S | Síra | In Czech = S | Sylffwr | In Welsh = S | Svovl | In Danish = S | Schwefel | In German = S | Θείο | In Greek = S | Sulfur | In English = S | Azufre | In Spanish = S | Väävel | In Estonian = S | Sufre | In Basque = S | گوگرد | In Persian = S | Rikki | In Finnish = S | Solfar | In Friulian = S | Xofre | In Galician = S | גופרית | In Hebrew = S | गन्धक | In Hindi = S | Sumpor | In Croatian = S | Souf | HT = S | Kén | In Hungarian = S | Ծծումբ | In Armenian = S | Belerang | In Indonesian = S | Sulfo | In Ido = S | Brennisteinn | In Icelandic = S | Zolfo | In Italian = S | 硫黄 | In Japanese = S | 황 | In Korean = S | Kibrît | In Kurdish = S | Schwiefel | In Letzeburgesh = S | Solfer | LI = S | Siera | In Lithuanian = S | Sērs | In Latvian = S | Pungatara | In Māori = S | Сулфур | In Macedonian = S | ഗന്ധകം | In Malayalam = S | Хүхэр | In Mongolian = S | सल्फर | MR = S | Swevel | NDS = S | Zwavel | In Dutch = S | Svovel | In Nynorsk = S | Svovel | In Norwegian = S | Sulfre | NOV = S | Sofre | In Occitan = S | Siarka | In Polish = S | Enxofre | In Portuguese = S | Salina | In Quechua = S | Sulf | In Romanian = S | Сера | In Russian = S | Surfi | In Sicilian = S | Sumpor | In Serbo-Croatian = S | Síra | In Slovak = S | Žveplo | In Slovenian = S | Squfuri | SQ = S | Сумпор | In Serbian = S | Walirang | SU = S | Svavel | In Swedish = S | Sulfuri | In Swahili = S | கந்தகம் | In Tamil = S | గంధకము | TE = S | กำมะถัน | In Thai = S | Kükürt | In Turkish = S | Сірка | In Ukrainian = S | Oltingugurt | In Uzbek = S | Lưu huỳnh | In Vietnamese = S | שװעבל | In Yiddisch = S | 硫 | In Chinese |
In Esperanto | → Chemistry |
| S | Serino = S | Serine | In English = S | سيرين | In Arabic = S | Serina | In Catalan = S | Serin | In Czech = S | Serin | In Danish = S | Serin | In German = S | Serina | In Spanish = S | Sérine | In French = S | 세린 | In Korean = S | Serin | In Croatian = S | Serin | In Indonesian = S | Serina | In Italian = S | סרין | In Hebrew = S | Serīns | In Latvian = S | Serin | In Letzeburgesh = S | Serinas | In Lithuanian = S | Serine | In Dutch = S | セリン | In Japanese = S | Serin | In Norwegian = S | Seryna | In Polish = S | Serina | In Portuguese = S | Серин | In Russian = S | Seriini | In Finnish = S | Serin | In Swedish = S | செர்ரீன் | In Tamil = S | Serin | In Turkish = S | Серин | In Ukrainian = S | 絲氨酸 | In Chinese |
In Esperanto | → Biochemistry, biophysics |
| SA | Simpla Abonanto | In Esperanto | → Newspapers, journalism |
| SAEST | Seminario pri Aplikado de Esperanto en Scienco kaj Tekniko | In Esperanto | → Congresses → Mathematics and natural sciences → Applied sciences, technology |
| SAT | Sennacieca Asocio Tutmonda (www.satesperanto.org) | In Esperanto | → Associations |
| SATEB | Sennacieca Asocio Tutmonda en Britio | In Esperanto | → Associations |
| Se | Seleno = Se | Sélénium | In French = Se | Selenium | In Afrikaans = Se | سيلينيوم | In Arabic = Se | Селен | In Belarusian = Se | Селен | In Bulgarian = Se | সেলেনিয়াম | In Bengali = Se | Selen | In Bosnian = Se | Seleni | In Catalan = Se | Seleniu | In Corsican = Se | Selen | In Czech = Se | Selen | In Danish = Se | Selen | In German = Se | Σελήνιο | In Greek = Se | Selenium | In English = Se | Selenio | In Spanish = Se | Seleen | In Estonian = Se | سلنیوم | In Persian = Se | Seleeni | In Finnish = Se | Seleni | In Friulian = Se | Selenio | In Galician = Se | סלניום | In Hebrew = Se | सेलेनियम | In Hindi = Se | Selenij | In Croatian = Se | Selenyòm | HT = Se | Szelén | In Hungarian = Se | Սելեն | In Armenian = Se | Selenium | In Indonesian = Se | Selenio | In Ido = Se | Selen | In Icelandic = Se | Selenio | In Italian = Se | セレン | In Japanese = Se | lurcmu | JBO = Se | 셀레늄 | In Korean = Se | Selenium | In Latin = Se | Selen | In Letzeburgesh = Se | Selenas | In Lithuanian = Se | Selēns | In Latvian = Se | Селен | In Macedonian = Se | सेलेनियम | MR = Se | Selen | NDS = Se | Seleen | In Dutch = Se | Selen | In Nynorsk = Se | Selen | In Norwegian = Se | Selèni | In Occitan = Se | Selen | In Polish = Se | Selênio | In Portuguese = Se | Silinyu | In Quechua = Se | Seleniu | In Romanian = Se | Селен | In Russian = Se | Sileniu | In Sicilian = Se | Selen | In Serbo-Croatian = Se | Selén | In Serbian = Se | Selen | In Slovenian = Se | Селен | In Serbian = Se | Selen | In Swedish = Se | Seleni | In Swahili = Se | செலீனியம் | In Tamil = Se | ซีลีเนียม | In Thai = Se | Selenyum | In Turkish = Se | Селен | In Ukrainian = Se | Selen | In Uzbek = Se | 硒 | In Chinese |
In Esperanto | → Chemistry |
| SEF | Sveda Esperanto-Federacio | In Esperanto | → Organizations and associations |
| SEJU | Svedia Esperantista Junulara Unuiĝo | In Esperanto | → Organizations and associations |
| SEK | Seula Esperanto-Kulturcentro | In Esperanto | → Civilization, culture, progress |
| SEK | Sorocaba Esperanto-Klubo | In Esperanto | → Organizations and associations |
| SEL | Skolta Esperanto-Ligo | In Esperanto | → Organizations and associations |
| SenAR | Sendai Astronomiaj Raportoj | In Esperanto | → Serial publications, periodicals → Astronomy |
| SerbEJO | Serbia Esperanto Junulara Organizo | In Esperanto | → Organizations and associations |
| SES | Slava Esperanto-Studado | In Esperanto | |
| SES | Svisa Esperanto-Societo (http://esperan.to/ses/) | In Esperanto | → Associations |
| SIA | Semajno de Internacia Amikeco | In Esperanto | |
| SKEJ | Slovakia Esperanta Junularo | In Esperanto | → Organizations and associations |
| SOMERE | SOmera MEzeŭropa REnkontiĵo | In Esperanto | |
| SPR | Senprograma Renkontiĝo | In Esperanto | → Congresses |
| STEB | Scienca kaj Teknika Esperanto-Biblioteko | In Esperanto | → Libraries → Mathematics and natural sciences → Applied sciences, technology |
| SUK | Someraj Universitataj Kursoj | In Esperanto | → Higher education, universities |
| SUS | Sanmarin(ec)a Universitata Sesio | In Esperanto | → Higher education, universities |
| SUS | Sanmarina Universitata Sesio | In Esperanto | → Higher education, universities |
| T | Treonino = T | Threonine | In English = T | Treonina | In Catalan = T | Threonin | In Czech = T | Threonin | In German = T | Treonina | In Spanish = T | Thréonine | In French = T | 트레오닌 | In Korean = T | Treonin | In Indonesian = T | Treonina | In Italian = T | תראונין | In Hebrew = T | Treonīns | In Latvian = T | Threonin | In Letzeburgesh = T | Treoninas | In Lithuanian = T | Threonine | In Dutch = T | トレオニン | In Japanese = T | Treonina | In Polish = T | Treonina | In Portuguese = T | Треонин | In Russian = T | Treoniini | In Finnish = T | Treonin | In Swedish = T | Treonin | In Turkish = T | Треонін | In Ukrainian = T | 蘇氨酸 | In Chinese |
In Esperanto | → Biochemistry, biophysics |
| T | Timino = T | Thymine | In English = T | ثايمين | In Arabic = T | Timina | In Catalan = T | Thymin | In Czech = T | Thymin | In Danish = T | Thymin | In German = T | Θυμίνη | In Greek = T | Timina | In Spanish = T | Timina | In Galician = T | Timina | In Italian = T | Thymine | In French = T | Timin | In Indonesian = T | תימין | In Hebrew = T | Timinas | In Lithuanian = T | Timin | In Hungarian = T | Thymine | In Dutch = T | チミン | In Japanese = T | Tymin | In Norwegian = T | Tymina | In Polish = T | Timina | In Portuguese = T | Тимин | In Russian = T | Timin | In Slovenian = T | Тимин | In Serbian = T | 胸腺嘧啶 | In Chinese = T | Тимін | In Ukrainian = T | Timin | In Turkish = T | Timin | In Serbo-Croatian = T | ไทมีน | In Thai = T | Tymiini | In Finnish = T | Tymin | In Swedish |
In Esperanto | → Genetics → Biochemistry, biophysics |
| TAdEN | Tutmonda Agado - Asocio de Esperantistaj Nefumantoj | In Esperanto | → Associations → Personal health and hygiene |
| TAKE | Tutmonda Asocio de Konstruistoj Esperantistaj (http://take.esperanto.free.fr) | In Esperanto | → Associations → Building |
| TAKE | Tutamerika Kongreso de Esperanto | In Esperanto | |
| TEC | Terminologia Esperanto-Centro | In Esperanto | → Artificial languages (linguistics) |
| TEF | Tuluzaj Esperantistaj Fervojistoj | In Esperanto | → Organizations and associations → Transport and postal services |
| TEJA | Tutmonda Esperantista Ĵurnalista Asocio | In Esperanto | → Associations → Newspapers, journalism |
| TEJK | Tut-Eŭropa Junulara Konferenco | In Esperanto | → Organizations and associations |
| TEJO | Tutmonda Esperanto Junulara Organizo (www.tejo.org) | In Esperanto | → Organizations and associations |
| TEL | Tutmonda Ekumena Ligo | In Esperanto | → Organizations and associations → Religion, theology |