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

He envisions a world where neighbors grow food to share with each other and those hardpan vacant lots and parkway strips between sidewalk and street are lush with birdsong, flowers and food-producing plants.

From Los Angeles Times • Jan. 11, 2022

On the 13th, he couldn’t get a 5 1/2-foot eagle putt to fall after hitting a 208-yard second shot from the desert hardpan.

From Seattle Times • Feb. 6, 2021

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

From "100 Sideways Miles" by Andrew Smith