American Heritage Dictionary
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Century Dictionary
GNU Webster's 1913
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WordNet
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Elsewhere on the web
The low-enriched uranium is "the fallback, the backup plan," he said.— The Oak Ridger Home RSS
"If we don't get flexibility, the fallback is a disaster," said Deputy Superintendent Chuck Morris.— NEWS updates from www.voiceofsandiego.org
Dishes that involve lentils and beans are often my cheap-eats fallback, and I enjoy eating them.
It is possible to set more than one fallback, as is shown in the example.— Linux Journal - The Original Magazine of the Linux Community
And the I.C.E. "fallback" component has been around FOR ABOUT SIXTY YEARS NOW ALREADY, on the RAILROADS and also in the LARGEST SHIPS on the HIGH SEAS.— Propeller Most Popular Stories

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