hardpan

American  

[hahrd-pan] / ˈhɑrdˌpæn /

noun

1. any layer of firm detrital matter, as of clay, underlying soft soil.

2. hard, unbroken ground.

3. the fundamental or basic aspect of anything; solid foundation; underlying reality.

   the hardpan of mathematical theory.

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hardpan British  

/ ˈhɑːdˌpæn /

noun

1. a hard impervious layer of clay below the soil, resistant to drainage and root growth

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hardpan Scientific  

/ härd′păn′ /

1. A hard, usually clay-rich layer of soil lying at or just below the ground surface, in which soil particles are cemented together by silica, iron oxide, calcium carbonate, or organic matter that has precipitated from water percolating through the soil. Hardpans do not soften when exposed to water.

2. Also called caliche

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Etymology

Origin of hardpan

An Americanism dating back to 1810–20; hard + pan ¹

Example Sentences

But collectively, we’re mining an irreplaceable commons that our grandchildren will inherit as hardpan.

From Salon • Jul. 12, 2025

Thembi Hanify and Mariah Ernst, 30-something veterans of surf media and marketing, also saw a fertile crack in the hardpan environment.

From New York Times • Jun. 16, 2024

Mike McCormack lives in Galway, Ireland, on a seacoast facing the Atlantic with rocky, unforgiving cliffs that give way to thin, hardpan soil.

From Los Angeles Times • Jan. 2, 2024

Previously, gardeners used rototillers, which would produce a fluffy soil on top but, after 50 years of tilling, created a hardpan clay beneath.

From Washington Post • Jul. 13, 2021

After breakfast, we hiked out across the hardpan of the lake bottom.

From "100 Sideways Miles" by Andrew Smith