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Based on the Random House Dictionary, © Random House, Inc. 2012.
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Online Etymology Dictionary, © 2010 Douglas Harper
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Dictionary of American Slang and Colloquial Expressions by Richard A. Spears.Fourth Edition.
Copyright 2007. Published by McGraw Hill.
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The Free On-line Dictionary of Computing, © Denis Howe 2010 http://foldoc.org
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The American Heritage® Dictionary of Idioms by Christine Ammer.
Copyright © 1997. Published by Houghton Mifflin.
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Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
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