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first principle

American  

noun

  1. any axiom, law, or abstraction assumed and regarded as representing the highest possible degree of generalization.


first principle British  

noun

  1. one of the fundamental assumptions on which a particular theory or procedure is thought to be based

  2. an axiom of a mathematical or scientific theory

"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

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.

As in medicine, the first principle of policymakers is “do no harm.”

From Barron's • Apr. 30, 2026

The first principle of politics is the opposite.

From The Wall Street Journal • Mar. 31, 2026

"We hope this ban is only the start of a reckoning between society and the tech companies that built these platforms with growth as their first principle instead of safety."

From BBC • Dec. 11, 2025

The first principle is that the president normally should not be using the military to engage in domestic law enforcement.

From Slate • Sep. 3, 2025

“Lay the stones level, that’s the first principle in keeping a wall from shifting and falling down. “The second is to lay the stones one on two, two on one.

From "On the Far Side of the Mountain" by Jean Craighead George

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