| Theoretiker | theorist theoretician theorizer |
| Theoretikerin | theorist |
| theoretisch | theoretical |
| Häretiker | heretic |
| Phonetiker | phonetician |
| Theokratie | theocracy |
| Theorie | theory |
| Rheometer | rheometer |
| Enuretiker | bedwetter |
| Fonetiker | phonetician |
| Helvetier | Helvetian |
| Genetiker | geneticist |
| Neurotiker | neurotic |
| Choleriker | choleric person |
| Theogonie | theogony |
| Theorbe | theorbo |
| Theresia | Teresa |
| Thermidor | Thermidor |
| Thioether | thioether |
| theokratisch | theocratic |