from The American Heritage® Dictionary of the English Language, 4th Edition

  • n. A basic truth, law, or assumption: the principles of democracy.
  • n. A rule or standard, especially of good behavior: a man of principle.
  • n. The collectivity of moral or ethical standards or judgments: a decision based on principle rather than expediency.
  • n. A fixed or predetermined policy or mode of action.
  • n. A basic or essential quality or element determining intrinsic nature or characteristic behavior: the principle of self-preservation.
  • n. A rule or law concerning the functioning of natural phenomena or mechanical processes: the principle of jet propulsion.
  • n. Chemistry One of the elements that compose a substance, especially one that gives some special quality or effect.
  • n. A basic source. See Usage Note at principal.
  • idiom in principle With regard to the basics: an idea that is acceptable in principle.
  • idiom on principle According to or because of principle.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. A fundamental assumption.
  • n. A rule used to choose among solutions to a problem.
  • n. Moral rule or aspect.
  • n. A rule or law of nature, or the basic idea on how the laws of nature are applied.
  • n. A fundamental essence, particularly one producing a given quality.
  • n. A beginning.
  • v. To equip with principles; to establish, or fix, in certain principles; to impress with any tenet or rule of conduct.

from the GNU version of the Collaborative International Dictionary of English

  • n. Beginning; commencement.
  • n. A source, or origin; that from which anything proceeds; fundamental substance or energy; primordial substance; ultimate element, or cause.
  • n. An original faculty or endowment.
  • n. A fundamental truth; a comprehensive law or doctrine, from which others are derived, or on which others are founded; a general truth; an elementary proposition; a maxim; an axiom; a postulate.
  • n. A settled rule of action; a governing law of conduct; an opinion or belief which exercises a directing influence on the life and behavior; a rule (usually, a right rule) of conduct consistently directing one's actions.
  • n. Any original inherent constituent which characterizes a substance, or gives it its essential properties, and which can usually be separated by analysis; -- applied especially to drugs, plant extracts, etc.
  • transitive v. To equip with principles; to establish, or fix, in certain principles; to impress with any tenet, or rule of conduct, good or ill.

from The Century Dictionary and Cyclopedia

  • To establish or fix in certain principles; impress with any tenet or belief, whether good or ill: used chiefly in the past participle.
  • n. Beginning; commencement.
  • n. Cause, in the widest sense; that by which anything is in any way ultimately determined or regulated.
  • n. An original faculty or endowment of the mind: as, the principle of observation and comparison.
  • n. A truth which is evident and general; a truth comprehending many subordinate truths; a law on which others are founded, or from which others are derived: as, the principles of morality, of equity, of government, etc. In mathematical physics a principle commonly means a very widely useful theorem.
  • n. That which is professed or accepted as a law of action or a rule of conduct; one of the fundamental doctrines or tenets of a system: as, the principles of the Stoics or of the Epicureans; hence, a right rule of conduct; in general, equity; uprightness: as, a man of principle.
  • n. In chem.: A component part; an element: as, the constituent principles of bodies.
  • n. A substance on the presence of which certain qualities, common to a number of bodies, depend. See proximate principles, under proximate.
  • n. In patent law, a law of nature, or a general property of matter, a rule of abstract science.
  • n. a certain important proposition concerning the equation
  • n. See the adjectives.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • n. a basic truth or law or assumption
  • n. a basic generalization that is accepted as true and that can be used as a basis for reasoning or conduct
  • n. a rule or standard especially of good behavior
  • n. (law) an explanation of the fundamental reasons (especially an explanation of the working of some device in terms of laws of nature)
  • n. rule of personal conduct
  • n. a rule or law concerning a natural phenomenon or the function of a complex system


Middle English, alteration of Old French principe, from Latin prīncipium, from prīnceps, prīncip-, leader, emperor; see per1 in Indo-European roots.
(American Heritage® Dictionary of the English Language, Fourth Edition)
From Old French principe, from Latin principium ("beginning, foundation"), from princeps ("first"); see prince. (Wiktionary)


  • Douglas sometimes says that all the States (and it is part of this same proposition I have been discussing) that have become free have become so upon his “great principle; ” that the State of Illinois itself came into the Union as a Slave State, and that the people, upon the “great principle” of Popular Sovereignty, have since made it a Free State.

    Speech of Hon. Abraham Lincoln

  • However, the key difference in principle is whether the people ` s liberty should be sacrificed to this end (despite scant evidence it provides the means).

    I, Pirate …

  • And I commented before that all the practical objections you raise are right, and any kind of "pure" national consumption tax of the sort I am discussing in principle is impossible in practice.

    Income Distribution Stories, Arnold Kling | EconLog | Library of Economics and Liberty

  • Ignorance about the creation that can't be overcome even in principle is agnosticism not atheism

    Dawkins and ID

  • Why, in principle, is it not possible to distinguish between natural phenomenon and a directed event in designating a most plausible cause?

    Assessing Causality

  • But it appears that Misubishi, at least in principle is commited to thinking slightly outside the box.

    i-MIEV SPORT: Mitsubishi Launches New Electric Sports Car | Inhabitat

  • The solution in principle is a weak dollar, which should provide export jobs somewhere in the US economy.

    Matthew Yglesias » One of Us

  • The solution in principle is a weak dollar, which should provide export jobs somewhere in the US economy ….

    Matthew Yglesias » One of Us

  • I repeat, the Nationalist movement in principle is honourable, and with it no self-respecting people can find fault, certainly not we British people.

    The Political Situation in India

  • The term principle is ambiguous, and commonly signifies merely a cognition that may be employed as a principle, although it is not in itself, and as regards its proper origin, entitled to the distinction.

    The Critique of Pure Reason

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