| Orthorexie | orthorexia |
| Orthodoxie | Orthodoxy |
| Orthoepie | orthoepy |
| Orthografie | orthography spelling |
| Orthopädie | orthopaedics orthoorthopedicsaedics |
| Orthohelium | orthohelium |
| Orthese | orthosis orthotic |
| Orthographie | orthography spelling |
| Orthopäde | orthopedist orthopaedist orthopaedic specialist orthopedic specialist orthopedic surgeon |
| Orthopädin | orthopaedic specialist orthopaedist orthopedic specialist orthopedist |
| orthodox | orthodox |
| Anorexie | anorexia anorexia nervosa |
| Neuorthodoxie | orthodoxy |
| Orthogon | rectangle |
| Orthoklas | orthoclase |
| Orthopyroxen | orthopyroxene |
| Portmonee | wallet |
| Orthofoto | orthophoto |
| Orthognathie | orthognathy orthognathysm |
| Orthoptist | orthoptist |