permafrost
[pur-muh-frawst, -frost]
- (in arctic or subarctic regions) perennially frozen subsoil.
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Origin of permafrost
Also called pergelisol.
Dictionary.com Unabridged
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for permafrost
Contemporary Examples
I wondered what would happen to the trees if some of the permafrost melted, allowing roots to expand in longer growing seasons.
permafrost
- ground that is permanently frozen, often to great depths, the surface sometimes thawing in the summer
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Word Origin
C20: from perma (nent) + frost
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
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Word Origin and History for permafrost
n.
1943, coined in English by Russian-born U.S. geologist Siemon W. Muller (1900-1970) from perm(anent) frost.
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Online Etymology Dictionary, © 2010 Douglas Harper
permafrost
[pûr′mə-frôst′]
- A layer of soil or bedrock that has been continuously frozen for at least two years and as long as tens of thousands of years. Permafrost can reach depths of up to 1,524 m (4,999 ft). It is found throughout most of the polar regions and underlies about one fifth of the Earth's land surface.
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The American Heritage® Science Dictionary
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