| Theologie | theology |
| Theologe | theologian |
| Theologin | theologian |
| Rheologie | rheology |
| Theogonie | theogony |
| Areologie | areology |
| Geologie | geology |
| Ideologie | ideology |
| Teleologie | teleology |
| Ethnologie | ethnology |
| Ethologie | ethology behavioural research |
| Tokologie | tocology |
| Topologie | topology |
| Typologie | typology |
| Theodosia | Feodosiya |
| Theosophie | theosophy |
| Theodolit | theodolite |
| Theorie | theory |
| theologisch | theological theologic |
| Ideologin | ideologue |