Vocabulary.com!

With its uniquely effective word learning system, the Vocabulary.com app helps you master words through a fun and addictive game. And its powered by the worlds smartest, fastest dictionary. USA TodayHONORS AND AWARDS TIMEs 50 Best Websites of the Year PC Magazines Top 100 Websites of the Year Tech & Learning Award of Excellence Webby Awards: Official Honoree in Education