An Etymological Dictionary of Astronomy and Astrophysics

Layer of soil or rock, at some depth beneath the surface, in which the temperature has been continuously below 0°C from a few to several thousands of years. It exists where summer heating fails to reach the base of the layer of frozen ground.

Etymology (EN): From perma(nent) + → frost.

Etymology (PE): Mândbašm, from mând, → permanent,

• bašm, → frost.