Free, straightforward, and attractive, Dictionary.com for Android does exactly what you expect. It quickly serves up definitions and synonyms in its ad-supported dictionary-thesaurus combo. There's a history screen for referencing words you've previously requested, and another to bring you the daily definition in English or Spanish. As for other tricks, you can text or SMS definitions to a friend and press to hear the word's pronunciation.
It's a solid effort that has brand name appeal for Internet vocabulary geeks, but the Android version lacks some of the power behind Dictionary.com on the Web--most notably, the translator and helpful articles--and on the BlackBerry--namely, integration with the app's context menu. We also wouldn't mind having the option of pulling in a thumbnail image where applicable. As a search-and-retrieve word application, however, this is a good start for those looking for a free reference app.