principle

Pluralprinciples

Formsprinciples, principling, principled

1. 1
   nouncountable

   A fundamental assumption or guiding belief that shapes how a person reasons or behaves.

   Like the foundation of a house: everything built above it depends on it.

   The committee's recommendations were grounded in a single guiding principle.

   Scientists often disagree about which principles should shape public policy.

   Similarpremise

   Note

   The founding sense is the one nearest its Latin root. Principium meant "beginning, foundation" and came from princeps, "first," the same word that gave English prince. A principle here is what reasoning starts from, which is why premise sits beside it as a synonym. The typical construction is principles to reason from, or the principle an argument rests on.

2. 2
   nouncountable or uncountable

   A moral rule or standard of right conduct that a person holds to.

   He resigned on principle rather than approve the layoffs.

   She would not compromise her principles for a quick profit.

   Similartenet

   Note

   The moral sense works both as a plural and as a mass noun. In the plural it means a person's set of convictions: I don't doubt your principles. Singular and without an article, it means integrity itself: a person of principle, or, in Letitia Elizabeth Landon's 1837 portrait of Lavinia, utterly without principle. The phrase the principle of the thing marks the point at stake as moral rather than practical.

3. 3
   nouncountable

   A rule that guides the choice among competing solutions to a problem.

   Engineers applied the principle of choosing the simplest design that met every requirement.

   When several fixes were possible, a guiding principle helped them rank the trade-offs.

   Similarrule, guideline, criterion

   Note

   Here the word names a working rule, usually in the shape the principle of plus its content. The principle of least privilege, for instance, holds that a process should get only the permissions it needs. Regulators use it the same way: the F.C.C.'s open-Internet principles, reported by Reuters in 2009, set out what network operators may and may not do.

4. 4
   nouncountable

   A law of nature, or the basic concept behind how such laws operate or are applied.

   Archimedes' principle explains why a heavy steel ship can float.

   The principle of conservation of momentum governs every collision.

   Similarlaw

   Note

   Physics names its principles. Some carry a discoverer's name in the possessive, as in Bernoulli's principle. Others are capitalized titles, like the Pauli Exclusion Principle, which keeps two fermions out of the same state. The word also stretches to the idea a machine runs on, as in the principle of the internal combustion engine. There it means the working mechanism rather than a law.

5. 5
   nouncountable

   A source or origin; that from which something proceeds: its fundamental substance, energy, or ultimate cause.

   Some early philosophers held fire to be the primal principle of the universe.

   They sought the first principle from which all existence flows.

   Similarsource, origin, cause, element

   Note

   This sense sits closest to the Latin principium, "beginning": a principle here is where something comes from or what drives it. When John Tillotson preached in 1664 that the soul of man is an active principle, he meant a source of action, not a rule the soul obeys. That distinction is worth keeping in mind whenever older theology or philosophy uses the word.

6. 6
   nouncountable

   A fundamental essence, especially one that produces a particular quality.

   Alchemists spoke of a fiery principle responsible for combustion.

   The sweet principle of the root was thought to give it its taste.

   Similaressence, element

   Note

   An older way of explaining qualities: a thing was bitter, sweet or alive because some principle within it made it so. The phrase vital principle, the something believed to make living things live, keeps this sense in circulation. Chemistry narrowed the idea into a tissue's characteristic compound, the actual substance behind the quality.

7. 7
   nouncountable

   A chemical compound within plant or animal tissue that is characteristic of it and largely peculiar to it, defining that tissue's character: as nicotine does in tobacco.

   Quinine is the active principle that makes cinchona bark useful against fever.

   Researchers extracted the principle responsible for the herb's calming effect.

   Similaringredient, constituent

   Note

   Here an abstract essence becomes something a chemist can name. William Gregory's Outlines of Chemistry (1845) calls cathartine "the bitter, purgative principle of senna," and the set phrase is the active principle: the one substance that makes a plant act as it does. It is a concrete narrowing of the "essence" meaning, so it often takes an of-phrase naming its plant or tissue, as nicotine is the principle of tobacco.

8. 8
   verbtransitive

   To instill principles in someone; to establish a person firmly in certain beliefs or rules of conduct.

   The old tutor sought to principle his pupils in the virtues of restraint and duty.

   They had principled the young heir in the strict doctrines of the church.

   Similarground, school, instruct, train, indoctrinate

   Note

   The verb takes a person as its object. In John Locke's Essay Concerning Humane Understanding (1689), it also takes a that-clause naming the belief instilled: let an enthusiast be principled that he or his teacher is inspired. The passive there means taught to hold the belief. Its past tense and past participle are both principled.

9. 9
   nouncountable

   An innate faculty or natural endowment that a person possesses from the start.

   Reason, the philosophers argued, is a principle native to all human minds.

   They regarded conscience as an original principle implanted in us.

   Similarfaculty, endowment

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