You mention key-value Objects in the tutorial. This might be a tad murky for some beginning programmers. For more information in the official AS3 documentation, users should search for "Associative Arrays
." These are also often referred to as Hash Tables, but you won't see that term crop up in the AS3 API.
I personally had a bit of trouble with these fiddly structures the first time I ran across them in Flash programming. AS3 approaches them in a rather odd fashion. Most other languages have specific classes reserved for them, while AS3 repurposes a base class.