principle

noun

1. A fundamental assumption or guiding belief.

   “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.”

   “Mr. Genachowski proposed codifying the new principles with four existing principles issued several years ago by the F.C.C. They say that network operators cannot prevent users from accessing lawful Internet content, applications and services of their choice, nor can they prohibit users from attaching nonharmful devices to the network.”

3. 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.”

   “Lavinia—shrewd, careless, clever; ready to meet any difficulty, however humiliating, that might occur; utterly without principle; confident in that good fortune, which she scrupled at no means of attaining—was the very type of the real.”

4. A rule or law of nature, or the basic idea on how the laws of nature are applied.

   “Bernoulli's principle”

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

   “The principle of the internal combustion engine”

   “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.”

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

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

6. A fundamental essence, particularly one producing a given quality.

   “the active principle”

   “Cathartine is the bitter, purgative principle of senna.”

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

   “The soul of man is an active principle.”

8. An original faculty or endowment.

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

9. (alt-of, misspelling)Misspelling of principal.
10. (obsolete)A beginning.

    “Doubting sad end of principle unsound.”

verb

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

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