| Primärschlüssel | primary key |
| privater Schlüssel | private key |
| Zimmerschlüssel | room key |
| Fremdschlüssel | foreign key |
| Rührschüssel | mixing bowl mortar |
| Tenorschlüssel | tenor clef |
| Türschlüssel | door key |
| Kreuzschlüssel | wheel brace |
| Maulschlüssel | open end spanner |
| Privatschule | public school |
| verschlüsselt | encrypted |
| Haustürschlüssel | front door key front-door key |
| verschlüsseln | encrypt cipher |
| Altschlüssel | alto clef |
| Bassschlüssel | F clef |
| Baßschlüssel | bass |
| Funkschlüssel | fob |
| Hauptschlüssel | master key |
| Hausschlüssel | housekey |
| Ringschluss | cyclization |