Definition of "hardpan" [hard•pan]

• A layer of hard subsoil or clay. Also called caliche. (noun)
• Hard, unbroken ground. (noun)
• A foundation; bedrock. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Caliche is also known as hardpan, calcrete, kankar (in India), or duricrust."
• "Some of the farmers down here tell me confidentially that "hardpan" has been found on their neighbors 'farms, but I have not talked with any one who has any on his own farm."
• "Among other impediments to water reaching the roots, such as hardpan, soil compaction, soil layering, and low salt, is a condition known as water recession."