frostline

[ frawst-lahyn, frost- ]

noun

1. the maximum depth at which soil is frozen.
2. the lower limit of permafrost.

Word History and Origins

Origin of frostline¹

An Americanism dating back to 1860–65; frost + line ¹

Example Sentences

Earlier this spring, Small stood on the ridge of the vineyard, gazing out at the white frostline that cut across the hills.

From Seattle Times

In the winter, the snakes slither into the crevices deep below the frostline and spend about eight months of the year there.

From US News