principle

noun prin·ci·ple \ ˈprin(t)-s(ə-)pəl , -sə-bəl \

Definition of principle

1 a :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

3 a :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

See principle defined for English-language learners

See principle defined for kids

principle vs. principal

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.

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

Recent Examples of principle from the Web

This is a democracy with deep faith in government, a driving principle throughout its five decades of existence — all under one party.

— jessica meyers, latimes.com, "Singapore has an idea to transform city life — but there may be a privacy cost," 28 Aug. 2017
Exactly 200 years ago, Ricardo published On the Principles of Political Economy and Taxation, explaining the doctrine of comparative advantage.

— george will, National Review, "Trump, the Novice Protectionist," 26 Aug. 2017
That has been sort of a guiding principle in my life.

— susannah hutcheson, USA TODAY College, "How I became a fashion mogul: Hillary Kerr," 25 Aug. 2017
WASHINGTON (AP) — President Donald Trump’s new Afghanistan strategy reveals some principles of a broader approach to foreign conflicts.

— josh lederman, The Seattle Times, "New Afghanistan plan could offer clues to ‘Trump Doctrine’," 23 Aug. 2017
These heinous acts are an assault on our nation’s values and threaten to move our country backward to a time when many had little regard for the principles of fairness, liberty and equality.

— beth py-lieberman, Smithsonian, "Smithsonian’s African American History Museum Releases Statement on Charlottesville and Confederate Memorials," 20 Aug. 2017
The Louisville attorney who represented Leachman, Sam Aguiar, said the case was more about principle and less about the money.

— darcy costello, The Courier-Journal, "Louisville lost a 'unique voice' when Robert Leachman was killed, family and friends say," 17 Aug. 2017
The equal treatment of all people is one of our nation’s bedrock principles.

— lucinda shen, Fortune, "Jamie Dimon on Why He Parted Ways With Trump: ‘Racism, Intolerance and Violence Are Always Wrong’," 16 Aug. 2017
The company has said the plant would employ 3,000 workers at the beginning but the state's agreement in principle with Foxconn has no minimum jobs requirement.

— lee bergquist, Milwaukee Journal Sentinel, "How would the Wisconsin Foxconn deal work? Here are some answers," 16 Aug. 2017

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.

Origin and Etymology of principle

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

NEW! Time Traveler

First Known Use: 14th century

See Words from the same year

PRINCIPLE Defined for English Language Learners

principle

noun

Definition of principle for English Language Learners

: 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