The Google Play Books app just received a substantial update, bringing the app to version 2.6.31 on compatible devices. Here's the changelog:
Added highlighting, notes, dictionary, "Places" info cards, translation, sepia mode, and sliding page-turn. Fixed crashes on launch on certain devices including HTC Wildfire.
In "Flowing Text" books, you can tap & hold to select some text and then
- See definition in dictionary info cards
- See a map and Wikipedia snippet in "Places" info cards, if the selected text is a place.