Dictionary is a well designed English dictionary application for iPhone & iPod Touch. At the core, it does two things. 1) Provides you the meaning of the words you input and 2) Provides synonyms for given words.
The application is designed with an intuitive interface. While the application is open, you can navigate back and forth between previous lookups.
The settings section lets you choose between dictionary mode and the Synonym mode.
The application gathers information from the internet and needs network connectivity for it to work.