| Quadratestadt | City of Squares |
| Quadragesima | Lent |
| Quadratmeter | square meter square metre |
| Quadratschädel | square head block |
| Quadratsekunde | second |
| Quadratzahl | square number |
| Quartett | quartet quartette |
| quadratisch | quadratic square |
| Gartenstadt | garden city |
| Quadratfuß | square foot |
| Quadrupede | quadruped |
| Quadrant | quadrant |
| Quadrat- | square |
| Quadrat | square |
| Quadratmeile | square mile |
| Quadratum | quadrate bone |
| Quadratur | quadrature |
| Quadratwurzel | square root |
| Quantität | quantity |
| Quarantäne | quarantine |