What does "a short nap" mean in English for Spanish?

In English for Spanish, "a short nap" means:

una breve siesta

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

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

• English for Spanish 3, Level 2, Scene 3