principle

noun
prin·​ci·​ple | \ ˈprin(t)-s(ə-)pəl How to pronounce principle (audio) , -sə-bəl\

Definition of principle

1a : a comprehensive and fundamental law, doctrine, or assumption
b(1) : a rule or code of conduct
(2) : habitual devotion to right principles a man of principle
c : the laws or facts of nature underlying the working of an artificial device
2 : a primary source : origin
3a : an underlying faculty or endowment such principles of human nature as greed and curiosity
b : an ingredient (such as a chemical) that exhibits or imparts a characteristic quality
4 capitalized, Christian Science : a divine principle : god
in principle
: with respect to fundamentals prepared to accept the proposition in principle

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Principle vs. Principal: Usage Guide

Although nearly every handbook and many dictionaries warn against confusing principle and principal, many people still do. Principle is only a noun; principal is both adjective and noun. If you are unsure which noun you want, read the definitions in this dictionary.

Principle vs. Principal

Yes, these two words are confusing; we see evidence of the misuse of both in newspapers and books which have been overseen by professional editors, so don’t feel bad if you have trouble with them. Principle only functions as a noun (such as “a comprehensive and fundamental law, doctrine, or assumption”); if you want it to be an adjective you must use the word principled. Principal, on the other hand, may function as a noun (such as the head of a school) or as an adjective (meaning “most important”). 

Examples of principle in a Sentence

Urban guerrilla warfare was futile against a thermonuclear superstate that would stop at nothing to defend the profit principle. — Philip Roth, American Pastoral, 1997 Better, of course, to take a higher road, operate on the principle of service and see if things don't turn out better … — Richard Ford, Independence Day, 1995 Pointlessness was life's principle, and it spread its sadness. — Arthur Miller, Timebends, 1987 His investment strategy is based on the principle that the stock market offers the best returns for long-term investors. the basic principles of hydraulics
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Recent Examples on the Web

Vatican spokesman Alessandro Gisotti confirmed that the guidelines’ fundamental principle is looking out for the best interests of the child. Nicole Winfield, The Seattle Times, "Priest’s son demands Vatican attention for clergy’s children," 20 Feb. 2019 The principle now is: not always with each other, but never against each other. Yaroslav Trofimov, WSJ, "The New Beijing-Moscow Axis," 1 Feb. 2019 The overarching principle behind the unmanned warships is to use them to overwhelm an enemy at sea, stretching and breaking an adversary’s ability to keep track of all the U.S. Navy can throw at it. Kyle Mizokami, Popular Mechanics, "What We Know About the U.S. Navy's Drone Fleet of the Future," 15 Jan. 2019 The housing market follows the old economic principle of price being a function of supply and demand, and demand is strong with the economy doing well and older millennials finally entering stages of life that lead to buying a home. Jeff Andrews, Curbed, "Housing market signaled potential future downturn in 2018," 21 Dec. 2018 Gravity, and all weighted blankets, works on the principle of Deep Touch Stimulation (DTS)-a form of therapeutic touch or holding that relaxes the nervous system. Sam Gutierrez, House Beautiful, "Everyone Needs A Chunky Knit Weighted Blanket," 11 Dec. 2018 Some online random number generators rely on algorithms, which means their output is, in principle, predictable; others depend on random physical phenomena. Sophia Chen, Science | AAAS, "Why are countries creating public random number generators?," 28 June 2018 The settlement in principle of the national master UPS agreement is subject to approval by UPS local unions, and yet to be resolved are supplemental agreements, according to the Teamsters. Kelly Yamanouchi, ajc, "UPS reaches tentative labor deal with Teamsters," 22 June 2018 Fifty-two percent of Americans would favor such a deal in principle, while 39 percent would oppose it. CBS News, "CBS News poll: Two-thirds of Americans say separating children, parents at border unacceptable," 18 June 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'principle.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of principle

14th century, in the meaning defined at sense 1a

History and Etymology for principle

Middle English, from Middle French principe, principle, from Old French, from Latin principium beginning, from princip-, princeps initiator — more at prince

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Last Updated

11 Mar 2019

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The first known use of principle was in the 14th century

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More Definitions for principle

principle

noun

English Language Learners Definition of principle

: a moral rule or belief that helps you know what is right and wrong and that influences your actions
: a basic truth or theory : an idea that forms the basis of something
: a law or fact of nature that explains how something works or why something happens

principle

noun
prin·​ci·​ple | \ ˈprin-sə-pəl How to pronounce principle (audio) \

Kids Definition of principle

1 : a general or basic truth on which other truths or theories can be based scientific principles
2 : a rule of conduct based on beliefs of what is right and wrong
3 : a law or fact of nature which makes possible the working of a machine or device the principle of magnetism

principle

noun
prin·​ci·​ple | \ ˈprin(t)-sə-pəl How to pronounce principle (audio) \

Medical Definition of principle

1 : a comprehensive and fundamental law, doctrine, or assumption
2 : an ingredient (as a chemical) that exhibits or imparts a characteristic quality the active principle of a drug

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More from Merriam-Webster on principle

Rhyming Dictionary: Words that rhyme with principle

Spanish Central: Translation of principle

Nglish: Translation of principle for Spanish Speakers

Britannica English: Translation of principle for Arabic Speakers

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