Update: As of February 2013 SnaPanda is no longer available.

SnaPanda is a free Android app that could help students expand their vocabulary. With SnaPanda installed on your phone you can point it at any clearly printed word on a page in a book, in a magazine, or on a sign and get the definition of that word. To do this just activate the app, point your phone’s camera at a word, and touch the word. SnaPanda then provides you with definitions for that word and examples of the word in use. SnaPanda users can save scanned words to a list for later review. Your lists can be shared via email, Twitter, and Facebook.

Here is a video explanation of SnaPanda.

Applications for Education
SnaPanda could be a great app for students to use when they visit a museum on a field trip. While reading placards associated with the artifacts they see in a museum they can use SnaPanda to get definitions of any words that are unfamiliar to them.