| Oktologie | octology |
| Ontologie | ontology |
| Otologie | otology |
| Ökologie | ecology |
| Ontologe | ontologist |
| Ontologin | ontologist |
| Motologie | motology |
| Skatologie | scatology |
| Zytologie | cytology |
| Oologie | oology |
| Ökologin | ecologist |
| Onkologie | oncology |
| Osteologie | osteology |
| Tokologie | tocology |
| Ökologe | ecologist |
| Önologie | oenology enology |
| Proktologin | proctologist |
| Oktole | octuplet |
| Proktologe | proctologist |
| Aretologie | aretology |