principle

Borrowed from Old French principe, from Latin prīncipium (“beginning, foundation”), from prīnceps (“first”); see prince.

• IPA^(key): /ˈpɹɪnsɪpəl/, /ˈpɹɪnsəpəl/

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• Hyphenation: prin‧ci‧ple
• Homophone: principal

principle (plural principles)

1. A fundamental assumption or guiding belief.
   • 2011 July 20, Edwin Mares, “Propositional Functions”, in The Stanford Encyclopedia of Philosophy, retrieved 2012-07-15:

     Let us consider ‘my dog is asleep on the floor’ again. Frege thinks that this sentence can be analyzed in various different ways. Instead of treating it as expressing the application of __ is asleep on the floor to my dog, we can think of it as expressing the application of the concept
          my dog is asleep on __
     to the object
          the floor
     (see Frege 1919). Frege recognizes what is now a commonplace in the logical analysis of natural language. We can attribute more than one logical form to a single sentence. Let us call this the principle of multiple analyses. Frege does not claim that the principle always holds, but as we shall see, modern type theory does claim this.

   We need some sort of principles to reason from.

2. A rule used to choose among solutions to a problem.

   The principle of least privilege holds that a process should only receive the permissions it needs.

3. (sometimes pluralized) Moral rule or aspect.

   I don't doubt your principles.

   You are clearly a person of principle.

   It's the principle of the thing; I won't do business with someone I can't trust.

4. (physics) A rule or law of nature, or the basic idea on how the laws of nature are applied.
   • 2013 July-August, Sarah Glaz, “Ode to Prime Numbers”, in American Scientist, volume 101, number 4:

     Some poems, echoing the purpose of early poetic treatises on scientific principles, attempt to elucidate the mathematical concepts that underlie prime numbers. Others play with primes’ cultural associations. Still others derive their structure from mathematical patterns involving primes.

   Bernoulli's Principle

   The Pauli Exclusion Principle prevents two fermions from occupying the same state.

   The principle of the internal combustion engine

5. A fundamental essence, particularly one producing a given quality.
   • Gregory

     Cathartine is the bitter, purgative principle of senna.

   Many believe that life is the result of some vital principle.

6. (obsolete) A beginning.
   • Edmund Spenser

     Doubting sad end of principle unsound.

7. A source, or origin; that from which anything proceeds; fundamental substance or energy; primordial substance; ultimate element, or cause.
   • Tillotson

     The soul of man is an active principle.

8. An original faculty or endowment.
   • Stewart

     those active principles whose direct and ultimate object is the communication either of enjoyment or suffering

• Principle ("moral rule"), as a noun, is often confused with principal, which can be an adjective ("most important") or a noun ("school principal"). A memory aid to avoid this confusion is: "The principal alphabetic principle places A before E".

• (moral rule or aspect): tenet

• prince
• principal
• principality

principle (third-person singular simple present principles, present participle principling, simple past and past participle principled)

1. (transitive) To equip with principles; to establish, or fix, in certain principles; to impress with any tenet or rule of conduct.
   • L'Estrange

     Governors should be well principled.

   • Locke

     Let an enthusiast be principled that he or his teacher is inspired.

• principle in Webster’s Revised Unabridged Dictionary, G. & C. Merriam, 1913.
• principle in The Century Dictionary, New York, N.Y.: The Century Co., 1911.