| Gruppentheorie | group theory |
| Graphentheorie | graph theory |
| Gruppentherapie | group therapy |
| Dramentheorie | dramatic theory |
| Gruppenehe | group marriage |
| Gruppenmord | holocaust |
| Gruppenphase | group stage |
| Knotentheorie | knot theory |
| Mengentheorie | set theory |
| Quantentheorie | quantum theory |
| Wellentheorie | wave model wave theory |
| Zahlentheorie | theory of numbers |
| Spieltheorie | game theory |
| Gruppenarbeit | groupwork |
| Gruppendenken | groupthink |
| Gruppendynamik | group dynamics |
| Gruppensex | group sex |
| Grippepneumonie | influenzal pneumonia |
| Frührentnerin | early retirement pensioner |
| Pongidentheorie | Pongidae hypothesis |