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

AWS says that Bedrock Managed Agents combine frontier AI models with AWS infrastructure, enabling customers to build OpenAI-powered agents in the cloud.

From Barron's • Apr. 28, 2026

Nuclear technology company Oklo will create a test reactor, and Bedrock Robotics moved 20 employees to test autonomous construction machinery.

From The Wall Street Journal • Apr. 24, 2026

Following Amazon’s recent re:Invent conference, Anmuth is confident that Amazon is improving its AI positioning with its custom Trainium chips, foundational model platform Bedrock and expanded partnerships.

From MarketWatch • Dec. 12, 2025

An attorney representing the neighborhood group declined to comment and Leon Benrimon, an official with developer Bedrock Property Group, could not be reached for comment.

From Los Angeles Times • Feb. 20, 2025

Bedrock lay 125 feet below grade, too deep for workers to reach with any degree of economy or safety using the construction methods available in the 1880s.

From "The Devil in the White City" by Erik Larson