Best English Dictionary App

By far the best I have tried—the interface is both fast and pleasant, and offers powerful search features that should be standard on any dictionary application (including wildcard, partial matches, homonyms, etc.).
This is the closest I have come to enjoying an English dictionary app more than its printed version. For French dictionaries, the Dixel app definitely brings dictionaries in the era of the portable computer.

Hypotyposis about Chambers Dictionary, v2.1