One of the many changes to iOS 5 has been the addition of a dictionary available for use in virtually any app that utilises word or text editing functionality. The screenshots above illustrate this feature whilst using Notes on the iPad and iPhone as well as a great third-party app known as PlainText.
To use this feature, select a word using either the “double tap” or “tap and hold” method, and the new Define button will be visible in the floating button menu. On the iPad, a text bubble will appear with the dictionary definition, tap outside the bubble to resume editing. The iPhone handles dictionary functionality in a slightly different manner: a separate window will open with the dictionary entry, tap the Done button at top right to resume editing after reading the definition.