| Kolbenmotor | piston engine |
| Kolbenente | red-crested pochard |
| Kollektor | collector |
| Boxermotor | boxer engine |
| Kommentator | commentator |
| Kondensator | capacitor |
| Kolbenhirse | foxtail millet |
| Kolben | club mace piston butt spadix flask |
| Kolonisator | colonizer |
| Kreiskolbenmotor | planetary piston engine rotary engine rotary piston engine |
| Zollbeamter | customs officer |
| Benzinmotor | Otto engine gasoline engine petrol engine spark ignition engine |
| Regenmoor | bogland |
| Sternmotor | radial engine |
| Dieselmotor | diesel engine |
| Wankelmotor | Wankel engine Wankel rotary engine |
| Kontor | office |
| Korrektor | proofreader |
| Konautor | coauthor |
| Konditor | confectioner |