| Drei-Kammer-System | tricameralism |
| Dreikammersystem | tricameralism |
| Zweiersystem | binary numeral system |
| Dreikantmaßstab | engineer's scale |
| dreihundertste | three hundredth |
| Larsen-System | Larsen's Opening Queen's Fianchetto Opening |
| Dateisystem | file system |
| Kristallsystem | crystal system |
| Sechsersystem | senary |
| Zehnersystem | decimal |
| Abwassersystem | sewage system sewerage wastewater system |
| Binärsystem | binary system |
| Dezimalsystem | decimal system |
| Dorfschützersystem | village guard system |
| Entladesystem | unload system |
| Immunsystem | immune system |
| Stellenwertsystem | positional notation system |
| Zeichensystem | sign system |
| Dreierwette | trifecta |
| Dreikönigsstern | Star of Bethlehem |