| Theologe | theologian |
| Theologie | theology |
| Theologin | theologian |
| Rheologie | rheology |
| Geologe | geologist |
| Ideologe | ideologist |
| Ethnologe | ethnologist |
| Ethologe | ethologist behavior scientist |
| Theogonie | theogony |
| Theorbe | theorbo |
| Theodor | Theodore |
| Theorie | theory |
| Areologie | areology |
| Geologie | geology |
| Ideologem | idea |
| Ideologie | ideology |
| Osteologe | osteologist |
| Teleologie | teleology |
| -ologe | -ologist |
| Bryologe | bryologist |