1. key (to open doors)

2. key (of musical instrument)

3. key (in heraldry)

4. spanner, wrench

5. faucet, tap, water tap, spigot

6. curly bracket ({ and })

7. switch (a device to turn electric current on and off or direct its flow)

8. lock (firearms)

9. hold (position or grip used to control the opponent) (wrestling)

10. a game where a small metal disc is thrown at a small metal structure (uncountable)