When literally stealing definition content from Wikipedia, Google.com does not state at the bottom of their "define:someword" search results that the results are released under the GNU documentation license. Under the terms of MediaWiki and GNU documentation license that the wikipedia is licensed under, Google is not playing fair game.

The wikipedia explicitely states that all content taken from the wikipedia must show and link to the GNU documentation license. Google does not follow or obey these terms when displaying content in request of a user searching for "define:word".

Google may think they can make thousands of dollars off copyrighted or GNU licensed content and not get noticed. The content Google is ripping or stealing without proper GFDL reference, is contributing content to their service, hence contributing to their profits.

Google violates the following requirement, clearly mentioned at the wikipedia website:

If you create a derivative version by changing or adding content, this entails the following:

• your materials in turn have to be licensed under GFDL

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License and Copyright Statement
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You must link to a local copy of the GFDL.
You must make it clear that the content from Wikipedia is available under the GFDL license.