per ‧ ma ‧ frost /ˈpɜːməfrɒst $ ˈpɜːrməfrɒːst/ BrE AmE noun [uncountable]
[ Date: 1900-2000 ; Origin: permanent + frost ]
a layer of soil that is always frozen in countries where it is very cold
per ‧ ma ‧ frost /ˈpɜːməfrɒst $ ˈpɜːrməfrɒːst/ BrE AmE noun [uncountable]
[ Date: 1900-2000 ; Origin: permanent + frost ]
a layer of soil that is always frozen in countries where it is very cold
Longman Dictionary of Contemporary English. Longman - Словарь современного английского языка. 2012