principle

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

|Updated on: 12 Aug 2018

Usage guide: principle vs. principal

Examples: principle in a Sentence

Editor's Note: principle vs. principal

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

Perhaps even more problematically, working with the Shah’s regime, a violator of political and human rights, undermined the very principles that Franklin purported to stand for—intellectual and political freedom.

— amanda laugesen, Smithsonian, "This Cold War-Era Publishing House Wanted To Share American Values With the World," 13 July 2018
Our city, our state, and our whole nation are divided in pitched arguments not only over the details of policy, but the essence of principle.

— WSJ, "Notable & Quotable: Larry Mone Retires," 12 July 2018
For such judges, restraint is a matter of principle.

— cass sunstein, star-telegram, "Does Trump's Supreme Court nominee have a personal political agenda?," 10 July 2018
The Colorado climate lawsuits involve a new application of an old principleLike the lawsuits filed in California and Rhode Island, the cases in Colorado invoke public nuisance law.

— umair irfan, Vox, "Why Colorado thinks it has a chance to make oil companies pay for climate change," 5 July 2018
De Havilland is the last surviving principle cast member of the movie, which also featured Hollywood icons Vivien Leigh and Clark Gable.

— danielle garrand, CBS News, "Last surviving "Gone With the Wind" star Olivia de Havilland turns 102," 2 July 2018
De Havilland, who lives in Paris, is the last surviving principle member of the classic 1939 film, which also starred Vivien Leigh and Clark Gable.

— maria pasquini, PEOPLE.com, "Gone With the Wind's Only Surviving Star Olivia de Havilland Turns 102," 2 July 2018
The Court’s decision today fails to safeguard that fundamental principle.

— anne branigin, The Root, "Sonia Sotomayor Reads the Supreme Court's Travel Ban Decision for Filth," 26 June 2018
The principle has generally been applied to the night-life realm—not to home goods.

— lizzie widdicombe, The New Yorker, "Midtown’s Mattress Speakeasy," 21 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.

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”).

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

in the meaning defined at sense 1a

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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