How can you figure out whether 鍵【かぎ】 means "lock" or "key"?


Recently, I forgot whether 鍵【かぎ】 meant lock or key, so I looked it up quickly
on my phone's dictionary... And then I found out that it actually means both.

What are the best ways to figure out if someone who is saying 鍵【かぎ】 is talking
about a lock or talking about a key? Is the intonation maybe different for
each meaning? Is there a way to ask which they are talking about? Is there a
common alternative word for one or both of them?

Definitely not as important as the main question, but I'm also wondering if
Japanese people sometimes get confused by this or if they just process it
naturally since they're used to 鍵【かぎ】?




The way I understand it is that `錠{じょう}` is generally used for "lock" and
`鍵{かぎ}` for "key". `鍵` can mean "lock" in some contexts however (this is
almost certainly incomplete):

>   * 鍵を掛ける - to lock (something)  
>  _(literally something like "[turn a key on
> (something)](http://eow.alc.co.jp/search?q=%E9%8D%B5%E3%82%92%E6%8E%9B%E3%81%91%E3%82%8B)")_
>   * 鍵が掛かっている/鍵が掛かった - (something) is locked
>   * 鍵を開ける - to unlock (something)
>   *
> [鍵を取り付ける](http://eow.alc.co.jp/search?q=%E9%8D%B5%E3%82%92%E5%8F%96%E3%82%8A%E4%BB%98%E3%81%91%E3%82%8B)
> \- "install a lock"
>   * [鍵が壊れている](http://eow.alc.co.jp/search?q=%E9%8D%B5%20%E5%A3%8A%E3%82%8C)
> \- "the lock is broken"
>   *
> [玄関に鍵をつける](http://dic.yahoo.co.jp/dsearch?p=%E9%8D%B5&enc=UTF-8&stype=0&dtype=0&dname=0ss)
> \- "attach a lock to the entrance"
>




The way I understand it is that `錠{じょう}` is generally used for "lock" and
`鍵{かぎ}` for "key". `鍵` can mean "lock" in some contexts however (this is
almost certainly incomplete):

>   * 鍵を掛ける - to lock (something)  
>  _(literally something like "[turn a key on
> (something)](http://eow.alc.co.jp/search?q=%E9%8D%B5%E3%82%92%E6%8E%9B%E3%81%91%E3%82%8B)")_
>   * 鍵が掛かっている/鍵が掛かった - (something) is locked
>   * 鍵を開ける - to unlock (something)
>   *
> [鍵を取り付ける](http://eow.alc.co.jp/search?q=%E9%8D%B5%E3%82%92%E5%8F%96%E3%82%8A%E4%BB%98%E3%81%91%E3%82%8B)
> \- "install a lock"
>   * [鍵が壊れている](http://eow.alc.co.jp/search?q=%E9%8D%B5%20%E5%A3%8A%E3%82%8C)
> \- "the lock is broken"
>   *
> [玄関に鍵をつける](http://dic.yahoo.co.jp/dsearch?p=%E9%8D%B5&enc=UTF-8&stype=0&dtype=0&dname=0ss)
> \- "attach a lock to the entrance"
>

