The free PONS Online Dictionary for iOS! Over 30 dictionaries in currently 13 different languages are at your disposal online.
Runs on iPhone and iPad, and requires iOS 5.0 or higher, and internet access.
The free PONS Vocabulary Trainer for iOS! Collect and practise the vocabulary you need wherever and whenever you wish!
Runs on iPhone, iPod touch and iPad, and requires iOS 4.3 or higher, and internet access.