| Orthopyroxen | orthopyroxene |
| Klinopyroxen | clinopyroxene |
| Orthodoxie | Orthodoxy |
| Orthogon | rectangle |
| Orthorexie | orthorexia |
| Orthoepie | orthoepy |
| Orthopäde | orthopedist orthopaedist orthopaedic specialist orthopedic specialist orthopedic surgeon |
| Orthopädie | orthopaedics orthoorthopedicsaedics |
| Orthopädin | orthopaedic specialist orthopaedist orthopedic specialist orthopedist |
| orthodox | orthodox |
| Pyroxen | pyroxene |
| Northumbrien | Northumbria |
| Orthofoto | orthophoto |
| Orthografie | orthography spelling |
| Orthoptist | orthoptist |
| orthogonal | orthogonal |
| Arthropode | arthropod |
| Arthrose | osteoarthritis arthrosis osteoartrit |
| Propylen | propylene |
| Propylon | propyleum |