Type in a keyword phrase in Google, such as php and you'll see a little hyper-linked word in blue at the top right named "definition". When clicked on, it used to take you to Dictionary.com, but On January 28th Danny Sullivan said, Google Completes Definition Move To Answers.com.
However, a post at WebmasterWorld shows that one person noticed this about two days prior to Danny's posting. Now the definition link for PHP takes you to Answers.com.