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subsoil

American  
[suhb-soil] / ˈsʌbˌsɔɪl /

noun

  1. the bed or stratum of earth or earthy material immediately under the surface soil.

subsoil British  
/ ˈsʌbˌsɔɪl /

noun

    1. Also called: undersoil.  the layer of soil beneath the surface soil and overlying the bedrock

    2. ( as modifier )

      a subsoil plough
"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

verb

  1. (tr) to plough (land) to a depth below the normal ploughing level and so break up the subsoil

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
subsoil Scientific  
/ sŭb′soil′ /

  1. In an ABC soil, the B horizon. The term was formerly used to mean the layer of earth below the humus or surface soil.

Other Word Forms

Etymology

Origin of subsoil

First recorded in 1790–1800; sub- + soil 1

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

The request from the firm, KoBold Metals, was made about six months ago and involved access to a large quantity of data on the Congolese subsoil in order to digitise it, Ouvry explained.

From Barron's • Feb. 12, 2026

After scraping you’ll likely be left with subsoil, layers of clay or sand, that lack the life-giving nutrients plants require.

From Los Angeles Times • Apr. 24, 2025

Excavators are then used to dig out the top soil and subsoil.

From BBC • Oct. 19, 2024

If you dig a burial pit into the subsoil, when you take the dead out and backfill it, the soil will be a different color.

From Science Magazine • Apr. 2, 2024

The subsoil beneath the palm trees was a raised beach, and generations of palms had worked loose in this the stones that had lain on the sands of another shore.

From "Lord of the Flies" by William Golding

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.