permafrost

American  

[pur-muh-frawst, -frost] / ˈpɜr məˌfrɔst, -ˌfrɒst /

noun

1. (in Arctic or subarctic regions) perennially frozen subsoil.

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permafrost British  

/ ˈpɜːməˌfrɒst /

noun

1. ground that is permanently frozen, often to great depths, the surface sometimes thawing in the summer

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permafrost Scientific  

/ pûr′mə-frôst′ /

1. 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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Etymology

Origin of permafrost

First recorded in 1943; perma(nent) + frost

Example Sentences

They found that pieces of amino acids from E. coli bacteria, if trapped in Martian permafrost or ice caps, could survive more than 50 million years even under constant cosmic radiation.

From Science Daily

It stretches northward into desolate permafrost regions flush with “oil sands” that produce about nine times as much crude as Alaska.

From The Wall Street Journal

Managing heat from a data center built on permafrost requires specialized engineering.

From The Wall Street Journal

Because the frozen permafrost was just a half meter beneath the active layer of soil, all the water on the tundra stayed near the surface.

From Literature

Those who think history is by its nature a sort of settled permafrost will be surprised to see how the discipline has changed over the past half century.

From The Wall Street Journal