| Optik | optics |
| Optiker | optician |
| Optikerin | optician |
| Koptin | Copt |
| Option | option |
| Haptik | haptics |
| Batik | batik |
| Gotik | Gothic |
| Noetik | noetic |
| Poetik | poetics |
| antik | ancient antique |
| Kopte | Copt |
| Optimum | optimum |
| Optode | optode |
| adoptiv | adoptive |
| Optativ | optative optative mood |
| Optimat | optimate |
| Synoptik | synoptic meteorology |
| optimal | optimal optimum |
| optisch | optic optical |