Saving information in Dictionary.app
I would love it if you could view your history or bookmark words, but I'm fairly sure that you can't. See, for example, the TUAW article "Apple updates Dictionary app in Lion, still has a long way to go":


  I would also love to be able to bookmark favorite words and create word lists where I can group similar words together for quick access.


I'm also unaware of any hacks or add-ons that would make this possible.