bedrock

American  

[bed-rok] / ˈbɛdˌrɒk /

noun

1. Geology. unbroken solid rock, overlaid in most places by soil or rock fragments.

2. bottom layer; lowest stratum.

3. any firm foundation or basis.

   Technical courses will be founded on a bedrock of sound, general education so as to produce a well-rounded engineer.

4. the fundamental principles, as of a teaching, belief, or science.

   Let's strip away the cant and get down to bedrock.

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adjective

1. basic; fundamental.

bedrock British  

/ ˈbɛdˌrɒk /

noun

1. the solid unweathered rock that lies beneath the loose surface deposits of soil, alluvium, etc

2. basic principles or facts (esp in the phrase get down to bedrock )

3. the lowest point, level, or layer

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bedrock Scientific  

/ bĕd′rŏk′ /

1. The solid rock that lies beneath the soil and other loose material on the Earth's surface.

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Etymology

Origin of bedrock

An Americanism dating back to 1840–50; bed + rock ¹

Explanation

Bedrock is the hard layer of rock beneath looser rocks and soil. In some places, the bedrock is exposed, while in others it lies deep underground. A geologist who's interested in studying the bedrock in different areas might have to dig through the various layers of soil to reach that bedrock. You can also use the word in a figurative way, to mean "the heart of the matter," or "the basic, fundamental principles." For example, you might say that fairness and freedom is the bedrock of a good government. The word combines bed — here meaning "plot of land" — and rock.

Example Sentences

Their analysis showed that the ice rested across a broad, relatively flat section of bedrock known as an ice plain.

From Science Daily • May 19, 2026

The prime minister said "the relationship between a minister and their officials relies on a bedrock of total transparency".

From BBC • May 6, 2026

He said part of it is the “culture and values…that’s the bedrock of Berkshire.”

From Barron's • May 3, 2026

“This failure to comply with the bedrock agreement among the seven Colorado River states is itself a serious development that Arizona will assess and will respond to accordingly in time,” it said.

From Los Angeles Times • Apr. 17, 2026

She spread her arms and the earth bent towards her - trees tilting, bedrock groaning, soil rippling in waves.

From "Blood of Olympus" by Rick Riordan