| Tetralogie | tetralogy |
| Tetraplegie | quadriplegia |
| Petrologie | petrology |
| Metrologie | metrology |
| Tetrarchie | tetrarchy |
| Neuralgie | neuralgia |
| Uteralgie | uteralgia |
| Pentalogie | pentalogy |
| Aretalogie | aretalogy |
| Genealogie | genealogy |
| Antrologie | arthrology |
| Astrologie | astrology |
| Ethologie | ethology behavioural research |
| Neurologie | neurology |
| Patrologie | patrology |
| Teleologie | teleology |
| Trilogie | trilogy |
| Tetrabromid | tetrabromide |
| Tetradymit | tetradymite |
| Tetragon | tetragon |