That's a pretty cool way to explore the dictionary! I suggest you make it so hovering over a blank definition dot will show the definition at the bottom, rather than having to click on it triggering an expansion / contraction. That would make it much easier to browse.
Pretty nifty. I would also kind of echo a suggestion sort of already offered by `vinceguidry: when expanding, I have to drag the screen over a la Google Maps style, it would be nice if I don't have to do it. Lower the amount of actions like this for the user.