permafrost

noun

per·​ma·​frost ˈpər-mə-ˌfrȯst 

: a permanently frozen layer at variable depth below the surface in frigid regions of a planet (such as earth)

Examples of permafrost in a Sentence

Recent Examples on the Web

Scientists have learned that as soon as summer temperatures thaw layers of the permafrost, its carbon turns into a bedazzling buffet for microbes. — Denise Hruby, Miami Herald, 31 July 2026

Researchers involved in the study expect these dynamics to intensify as flash droughts become more common, groundwater levels continue to decline, and permafrost retreats across the north. — Phil De Luna, Forbes.com, 27 July 2026

As Earth warms, an important source of methane is thawing permafrost, the permanently frozen ground found mostly in the Arctic. — Vahe Peroomian, The Conversation, 13 July 2026

Unlike with other major methane sources, such as belching cattle or melting permafrost, the technology to curb emissions from oil and gas operations is already viable, and fairly cheap. — Alex Cuadros, ProPublica, 16 June 2026

Word History

Etymology

permanent + frost

First Known Use

1943, in the meaning defined above

Rhymes for permafrost

• holocaust
• accost
• crisscrossed
• defrost
• embossed
• exhaust
• recrossed
• uncrossed
• bossed
• cost
• crossed
• dost

Kids Definition

permafrost

noun

per·​ma·​frost ˈpər-mə-ˌfrȯst 

: a permanently frozen layer at variable depth below the surface in frigid regions of a planet (as earth)