| Oktant | Octans |
| Aktant | agent complement |
| Oktal- | octal |
| Oktave | octave octonion Cayley algebra Cayley numbers |
| Oktett | octet |
| oktal | octal |
| Mutant | mutant |
| Octan | octane |
| Votant | votant |
| mokant | sardonic mockingbird |
| Kant | Kant |
| Oktagon | octagon |
| Oktaeder | octahedron |
| Oktole | octuplet |
| Reaktant | reactant |
| Diktat | dictation dictate |
| Natan | Nathan |
| Sutane | cassock |
| Titanit | titanite |
| Wotan | Odin |