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

“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

It became the bedrock upon which Palantir built its Artificial Intelligence Platform.

From MarketWatch • Apr. 4, 2026

The leftover carbon dioxide will be stored deep beneath the North Sea in sedimentary bedrock and will gradually mineralize over time.

From The Wall Street Journal • Mar. 26, 2026

These are impressive stats in bedrock categories essential for Augusta success.

From BBC • Mar. 23, 2026

Her voice resonated across the landscape, shaking the bedrock under Jason’s feet.

From "Blood of Olympus" by Rick Riordan