| Ottokar : Happy fighter. |
| Omjaa : Born of Cosmic Unity; Born from Om; Sacred Being, Born of Cosmic Unity, Born from Om, Sacred Being |
| Odell : Little wealthy one; ode; otter |
| Ozer : God's helper |
| Olden : |
| Orabella : Prayerful |
| Ocie : |
| Oszkar : Hungarian form of Oscar 'leaping warrior'. |
| Ogdan : Oak valley |
| Oshmi : Personality, Free from anything that dulls or dims |