Dictionary.com

permafrost

[ pur-muh-frawst, -frost ]
/ ˈpɜr məˌfrɔst, -ˌfrɒst /
Save This Word!

noun
(in Arctic or subarctic regions) perennially frozen subsoil.
QUIZ
ARE YOU A TRUE BLUE CHAMPION OF THESE "BLUE" SYNONYMS?
We could talk until we're blue in the face about this quiz on words for the color "blue," but we think you should take the quiz and find out if you're a whiz at these colorful terms.
Question 1 of 8
Which of the following words describes “sky blue”?
Meet Grammar CoachWrite or paste your essay, email, or story into Grammar Coach and get grammar helpImprove Your Writing
Meet Grammar CoachImprove Your Writing
Write or paste your essay, email, or story into Grammar Coach and get grammar help
Also called pergelisol.

Origin of permafrost

First recorded in 1943; perma(nent) + frost
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2021

How to use permafrost in a sentence

British Dictionary definitions for permafrost

permafrost
/ (ˈpɜːməˌfrɒst) /

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

Word Origin for permafrost

C20: from perma (nent) + frost
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for permafrost

permafrost
[ pûrmə-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.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
FEEDBACK