I think what he means is that it's not actually the array you're working with, so the name is misleading in this context. It's the underlying object. So if I ha

I think what he means is that it's not actually the array you're working with, so the name is misleading in this context. It's the underlying object. So if I have var a : Array = []; a['property'] = 'value'; , then I'm setting a property of the object, not an element in the array. It works just as well with var b : Object = {}; b['property'] = 'value';