You use it online, and beginning on Wednesday, you'll be able to use the popular Dictionary.com reference service on your iPhones and iPod Touches.
The free Dictionary.com for iPhone is straightforward, but attractive, and has one or two highlights that give it some interest. It isn't the only dictionary application for iPhone by a long shot, but it is a solid effort that has brand name appeal for Internet vocabulary geeks--plus, it's got those helpful tidbits we mentioned. For instance, after typing a search term, you can switch between the dictionary definition and thesaurus without losing your word. Also, the definitions and synonyms are preloaded into the app, which means your world of words won't go dark if you lose Wi-Fi or signal.
With an intact data connection, the app can read your definition aloud. Logophiles who want more vocabulary excitement can tune into the Word of the Day feature on the phone, and will be prompted to sign up for the e-mail definition delivery service as well.
The iPhone app is missing some of the power behind Dictionary.com on the Web--most notably, the translator and helpful articles. As a search-and-retrieve word application, however, this is a good start for those looking for a free reference app or who are trained to prefer Dictionary.com's experience.