This app doesn't just show you the definitions of the words you look up... it also ensures that you remember each word down the road as well.

Here's how it works. For every word you look up, you will receive review sessions that simply ask if you remember the definition of the word. If you do, you move on to the next review. If you fail to remember the definition, the review cycle for this word starts over.

Here's the magic. The reviews start out spaced closely together. Then over time, the distance between reviews expands. Eventually if you can go a month and still remember the word, chances are that you will remember that word for the rest of your life!

How's that for building and expanding your vocabulary!?