| Oktole | octuplet |
| Oktal- | octal |
| Oktave | octave octonion Cayley algebra Cayley numbers |
| Oktober | October |
| oktal | octal |
| Citole | citole |
| Töle | cur |
| Opole | Opole |
| Oktant | Octans |
| Doktor | doctor physican |
| Oktaeder | octahedron |
| Oktett | octet |
| Oktogon | octagon |
| Oktologie | octology |
| Oktopus | octopus |
| Laktose | lactose |
| Aktor | actuator |
| Bitola | Bitola |
| Ontologe | ontologist |
| Systole | systole |