What does "key" mean in English for Spanish?

In English for Spanish, "key" means:

llave

Listen to "key": (If you have an HTML5 enabled browser, you can listen to the native audio below)

This is a word that is used in the GamesForLanguage English for Spanish Language Game in the following scenes:

• English for Spanish 4, Level 3, Scene 1
• English for Spanish 4, Level 3, Scene 2