Meaning & use
permafrost
Last updated
Meaning
noununcountabletechnical
Ground that stays frozen for at least two years in a row, found in very cold regions.
Grammar: Used as a mass noun; it does not take a plural or an article in general statements.
Patterns
- permafrost melts
- layer of permafrost
- permafrost region
The house was built on permafrost, so its foundations shifted as the ground thawed.
Scientists are studying how quickly permafrost is melting in the Arctic.
Roads in Siberia often crack because they sit on top of permafrost.
Common combinations
- permafrost melts
- When permafrost melts, it releases stored carbon into the atmosphere.
- layer of permafrost
- A thick layer of permafrost lies just below the surface.
- permafrost region
- Building in permafrost regions requires special engineering.
- thawing permafrost
- Thawing permafrost can cause the ground to collapse suddenly.
Practice
Which sentence uses 'permafrost' correctly?
Choose one answer.
Permafrost is defined by staying frozen for at least two consecutive years, so option 1 is correct. Option 0 describes ordinary seasonal freezing, not permafrost. Option 2 treats permafrost as a movable object, and option 3 contradicts its meaning.
Make it your own
Write a sentence using “permafrost”, then check it and compare it with the examples above.