|1.||a standard or rule of personal conduct: a man of principle|
|2.||(often plural) a set of such moral rules: he'd stoop to anything; he has no principles|
|3.||adherence to such a moral code; morality: it's not the money but the principle of the thing; torn between principle and expediency|
|4.||a fundamental or general truth or law: first principles|
|5.||the essence of something: the male principle|
|6.||a source or fundamental cause; origin: principle of life|
|7.||a rule or law concerning a natural phenomenon or the behaviour of a system: the principle of the conservation of mass|
|8.||an underlying or guiding theory or belief: the hereditary principle; socialist principles|
|9.||chem a constituent of a substance that gives the substance its characteristics and behaviour: bitter principle|
|10.||in principle in theory or essence|
|11.||on principle because of or in demonstration of a principle|
|usage Principle and principal are often confused: the principal (not principle) reason for his departure; the plan was approved in principle (not in principal)|
"It is often easier to fight for principles than to live up to them." [Adlai Stevenson, speech, New York City, Aug. 27, 1952]Hence principled "moral" (1697). Scientific sense of "general law of nature" is recorded from 1802.
principle prin·ci·ple (prĭn'sə-pəl)
A basic truth, law, or assumption.
A rule or law concerning the functioning of natural phenomena or mechanical processes.
One of the elements composing a chemical compound, especially one that gives some special quality or effect.
The essential ingredient in a drug.
Fundamentally, in general, but not necessarily in all particulars. For example, The diplomats accepted the idea in principle but would rely on experts to work out all the details. [Early 1800s]