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

Definition of principle

  1. 1a :  a comprehensive and fundamental law, doctrine, or assumptionb (1) :  a rule or code of conduct (2) :  habitual devotion to right principles a man of principlec :  the laws or facts of nature underlying the working of an artificial device

  2. 2 :  a primary source :  origin

  3. 3a :  an underlying faculty or endowment such principles of human nature as greed and curiosityb :  an ingredient (such as a chemical) that exhibits or imparts a characteristic quality

  4. 4 capitalized, Christian Science :  a divine principle :  god

in principle

  1. :  with respect to fundamentals prepared to accept the proposition in principle

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

  1. Urban guerrilla warfare was futile against a thermonuclear superstate that would stop at nothing to defend the profit principle. —Philip Roth, American Pastoral, 1997

  2. 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

  3. Pointlessness was life's principle, and it spread its sadness. —Arthur Miller, Timebends, 1987

  4. His investment strategy is based on the principle that the stock market offers the best returns for long-term investors.

  5. the basic principles of hydraulics

Recent Examples of principle from the web

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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

First Known Use: 14th century

PRINCIPLE Defined for English Language Learners


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

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

PRINCIPLE Defined for Kids


noun prin·ci·ple \ˈprin-sə-pəl\

Definition of principle for Students

  1. 1 :  a general or basic truth on which other truths or theories can be based scientific principles

  2. 2 :  a rule of conduct based on beliefs of what is right and wrong

  3. 3 :  a law or fact of nature which makes possible the working of a machine or device the principle of magnetism

Medical Dictionary


noun prin·ci·ple \ˈprin(t)-sə-pəl\

Medical Definition of principle

  1. 1:  a comprehensive and fundamental law, doctrine, or assumption

  2. 2:  an ingredient (as a chemical) that exhibits or imparts a characteristic quality the active principle of a drug

Seen and Heard

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a trip made at another's expense

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