| ovulum | Samenanlage |
| ovum | Ei |
| Owain Glyndwr | Owain Glyndwr |
| Owambo | Ovambo |
| Owamboland | Ovamboland |
| Owen | Owen |
| Owen County | Owen County |
| Owen Seymour Arthur | Owen Arthur |
| Owen Stanley-gebergte | Owen-Stanley-Gebirge |
| Owen Willans Richardson | Owen Willans Richardson |
| Owen Wilson | Owen Wilson |
| Owensboro | Owensboro |
| Owingen | Owingen |
| Ownage | Computerspieler-Jargon |
| Owschlag | Owschlag |
| Owsley County | Owsley County |
| Owyhee County | Owyhee County |
| Oxaalzuur | Oxalsäure |
| Oxalaat | Oxalat |
| Oxalidales | Sauerkleeartige |
| Oxazepam | Oxazepam |
| Oxelösund | Oxelösund |
| Oxfam International | Oxfam |
| Oxford | Oxford |
| Oxford Circus | Oxford Circus |
| Oxford Classical Dictionary | The Oxford Classical Dictionary |
| Oxford County | Oxford County |
| Oxford English Dictionary | Oxford English Dictionary |
| Oxford Street | Oxford Street |
| Oxford United | Oxford United |
| Oxfordien | Oxfordium |
| Oxfordshire | Oxfordshire |
| Oxidatie | Oxidation |
| Oxidatietoestand | Oxidationszahl |
| Oxidatieve fosforylatie | Oxidative Phosphorylierung |
| Oxidatieve fosforylering | Atmungskette |
| Oxidator | Oxidationsmittel |
| Oxide | Oxide |
| oxideren | rosten |
| Oxime | Oxime |
| Oxnard | Oxnard |
| oxo | Käsekasten |
| Oxonium | Oxonium |
| Oxycodon | Oxycodon |
| oxydatie | Rost |
| oxyde | Oxid |
| oxyderen | oxidieren |
| Oxymoron | Oxymoron |
| Oxyrrhynchus | Oxyrhynchos |
| Oxytocine | Oxytocin |
| Oxyuranus | Taipane |
| Oy-Mittelberg | Oy-Mittelberg |
| Oybin | Oybin |
| Oyo | Oyo |
| Oyten | Oyten |
| Oz | OZ |
| Ozama | Río Ozama |
| Ozamis City | Ozamis City |
| Ozark | Ozark |
| Ozark County | Ozark County |
| Ozaukee County | Ozaukee County |
| Ozimek | Ozimek |
| Ozjorsk | Osjorsk |
| ozon | Ozon |
