| Orthoptist | orthoptist |
| Orthoepie | orthoepy |
| Orthoklas | orthoclase |
| Orthonitrat | orthonitrate |
| Porträtist | portraitist |
| Orthopäde | orthopedist orthopaedist orthopaedic specialist orthopedic specialist orthopedic surgeon |
| Orthopädie | orthopaedics orthoorthopedicsaedics |
| Orthopädin | orthopaedic specialist orthopaedist orthopedic specialist orthopedist |
| Arthritis | arthritis |
| Methodist | Methodist |
| Protist | protist |
| Orthodoxie | Orthodoxy |
| Orthogon | rectangle |
| Orthohelium | orthohelium |
| Orthorexie | orthorexia |
| Shortlist | short list |
| ortsfest | sessile |
| Anorthosit | anorthosite |
| Kortholt | kortholt |
| Orthese | orthosis orthotic |