| Ontologe | ontologist |
| Ontologie | ontology |
| Onkologe | oncologist |
| Önologe | enologist |
| Ontologin | ontologist |
| Oktologie | octology |
| Otologie | otology |
| Onkologie | oncology |
| Osteologe | osteologist |
| Ökologe | ecologist |
| Önologie | oenology enology |
| Deontologie | deontology |
| Odontologie | odontology |
| Entomologe | entomologist |
| Histologe | histologist |
| Knastologe | jailbird |
| Onomatologe | onomastician |
| Motologie | motology |
| Neonatologe | neonatologist |
| Oktole | octuplet |