| Graphentheorie | graph theory |
| Gruppentheorie | group theory |
| Dramentheorie | dramatic theory |
| Quantentheorie | quantum theory |
| Zahlentheorie | theory of numbers |
| Gruppentherapie | group therapy |
| Knotentheorie | knot theory |
| Mengentheorie | set theory |
| Wellentheorie | wave model wave theory |
| Spieltheorie | game theory |
| Sprachtheorie | linguistic theory theory of language |
| Grammatiktheorie | grammar |
| Graphikerin | graphic designer |
| Graphitfluorid | graphite fluoride |
| Taphephobie | taphephobia |
| Krähenbeere | crowberry |
| Präsentatorin | presenter |
| Pongidentheorie | Pongidae hypothesis |
| Eichtheorie | gauge theory |
| Chaostheorie | chaos theory |