| Ontologin | ontologist |
| Ontologie | ontology |
| Onkologin | oncologist |
| Önologin | oenologist |
| Ontologe | ontologist |
| Oktologie | octology |
| Otologie | otology |
| Osteologin | osteologist |
| Ökologin | ecologist |
| Onkologie | oncology |
| Önologie | oenology enology |
| Deontologie | deontology |
| Odontologie | odontology |
| ontologisch | ontological |
| Entomologin | entomologist |
| Histologin | histologist |
| Knastologin | jailbird |
| Neonatologin | neonatologist pediatrician |
| Onomatologin | onomastician |
| Politologin | political scientist |