북극이나 고산 지대에서 1년 내내 얼어 있는 상태로 유지되는 땅속의 층.
A thick layer of soil, rock, or sediment beneath the Earth's surface that remains frozen for at least two consecutive years, primarily found in polar regions.
예문:
"The melting of the Arctic permafrost releases significant amounts of methane into the atmosphere."
"Engineers must account for the stability of the permafrost when designing pipelines in northern regions."
"Global warming is causing the permafrost to thaw at an unprecedented rate."