| Mengentheorie | set theory |
| Wellentheorie | wave model wave theory |
| Dramentheorie | dramatic theory |
| Mengenlehre | set theory theory of sets |
| Knotentheorie | knot theory |
| Pongidentheorie | Pongidae hypothesis |
| Quantentheorie | quantum theory |
| Zahlentheorie | theory of numbers |
| Mengentext | body text |
| Graphentheorie | graph theory |
| Gruppentheorie | group theory |
| Eichtheorie | gauge theory |
| Zelltheorie | cell theory |
| M-Theorie | M-theory |
| Musiktheorie | music theory |
| Spieltheorie | game theory |
| Systemtheorie | system theory |
| Manganometrie | manganometry |
| Menagerie | menagerie |
| Mentorin | mentor |