| Klartraum | lucid dream |
| klarträumen | dream lucidly |
| Warteraum | lounge |
| Khartum | Khartoum |
| Alptraum | nightmare |
| Haftraum | cell |
| Tagtraum | daydream |
| Albtraum | nightmare bad dream |
| Luftraum | airspace |
| Altarraum | chancel presbytery |
| Laderaum | hold loading space |
| Klamauk | ballyhoo noise |
| Klanglaut | sonorant |
| Klangtreue | fidelity |
| Klara | Clara |
| Klathrat | clathrate |
| Klärgrube | septic tank |
| Kladogramm | cladogram |
| Klartext | cleartext straight talk |
| Klassenraum | classroom |