| Oryol | Orjol |
| Oryol Oblast | Orjol oblast |
| Oryza | Ris |
| Orzens | Orzens |
| Orăştie | Orăştie |
| OS | Operativsystem |
| Osage County | Osage County |
| Osage Nation | Osage |
| Osaka | Osaka |
| Osaka Bay | Osakabukten |
| Osaka Castle | Osaka |
| Osaka Municipal Subway | Osakas tunnelbana |
| Osaka Prefecture | Osaka prefektur |
| Osakeyhtiö | Osakeyhtiö |
| Osama bin Laden | Usama bin Ladin |
| Osamu Tezuka | Osamu Tezuka |
| Osan | Osan |
| Osborne House | Osborne House |
| Osborne Reynolds | Osborne Reynolds |
| Osby Municipality | Osby kommun |
| Oscan language | Oskiska |
| Oscar | Påfågelciklid |
| Oscar class submarine | Oscar |
| Oscar de la Hoya | Oscar de la Hoya |
| Oscar Fredrik Church | Oscar Fredriks kyrka |
| Oscar Gustave Rejlander | Oscar Gustave Rejlander |
| Oscar Gutierrez | Rey Mysterio |
| Oscar Hammerstein II | Oscar Hammerstein |
| Oscar I of Sweden | Oscar I |
| Oscar II of Sweden | Oscar II |
| Oscar Luigi Scalfaro | Oscar Luigi Scalfaro |
| Oscar Montelius | Oscar Montelius |
| Oscar Niemeyer | Oscar Niemeyer |
| Oscar Peterson | Oscar Peterson |
| Oscar Reutersvärd | Oscar Reutersvärd |
| Oscar Robertson | Oscar Robertson |
| Oscar Ruggeri | Óscar Ruggeri |
| Oscar Temaru | Oscar Temaru |
| Oscar Wendt | Ozcar Wendt |
| Oscar Wilde | Oscar Wilde |
| Oscarsborg Fortress | Oscarsborg |
| Osceola County | Osceola County |
| Oschatz | Oschatz |
| Osci | Osker |
| oscillate | svänga |
| oscillation | svängning |
| oscillator | oscillator |
| oscillatory | svängande |
| Osco | Osco |
| osculation | oskulation |
| Oseberg | Osebergsskeppet |
| Oseberg ship | Osebergsskeppet |
| Osella | Osella |
| Oseltamivir | Tamiflu |
| Osen | Osen kommun |
| Osgiliath | Osgiliath |
| Osh Province | Osj |
| Oshare kei | Oshare kei |
| Osho | Osho |
| Oshun | Oshun |
| OSI model | OSI-modellen |
| osier | vide |
| osier basket | mjärde |
| Osijek | Osijek |
| Osilnica | Osilnica |
| Osip Mandelstam | Osip Mandelstam |
| Osiris | Osiris |
| Osiris Shoes | Osiris |
| Oskar Backlund | Johan Oskar Backlund |
| Oskar Dirlewanger | Oskar Dirlewanger |
| Oskar Klein | Oskar Klein |
| Oskar Kokoschka | Oskar Kokoschka |
| Oskar Lafontaine | Oskar Lafontaine |
| Oskar Schindler | Oskar Schindler |
| Oskar-Helene-Heim | Oskar-Helene-Heim |
| Oskarshamn Municipality | Oskarshamns kommun |
| Oskarshamn Nuclear Power Plant | Oskarshamns kärnkraftverk |
| Oskemen | Öskemen |
| Oslo | Oslo |
| Oslo Accords | Osloprocessen |
| Oslo Cathedral | Oslo domkyrka |
| Oslo City Hall | Oslo rådhus |
| Oslo Spektrum | Oslo Spektrum |
| Oslo Stock Exchange | Oslo börs |
| Oslo T-bane | Oslos tunnelbana |
| Oslofjord | Oslofjorden |
| Oslotunnelen | Oslotunnelen |
| Osman I | Osman I |
| Osman III | Osman III |
| Osmaniye Province | Osmaniye |
| Osmanli | Osmanska dynastin |
| Osmanli Dynasty | Osmanska dynastin |
| osmium | osmium |
| osmosis | osmos |
| osmotic | osmotisk |
| Osmotrophy | Osmotrofi |
| Osmunda regalis | Safsa |
| Osmussaar | Odensholm |
| Osnabrück | Osnabrück |
| Osogna | Osogna |
| Osorno Province | Osorno |
| osprey | fiskgjuse |
| Osram | Osram |
| Osroene | Osrhoëniska riket |
| Ossa | Ossa |
| osseous | ben- |
