principle

nouns

a basic generalization that is accepted as true and that can be used as a basis for reasoning or conduct
"their principles of composition characterized all their works"
a rule or standard especially of good behavior
"a man of principle"; "he will not violate his principles"
is a type of (narrower)
an ideal accepted by some individual or group
"he has old-fashioned values"
a basic truth or law or assumption
"the principles of democracy"
is a type of (narrower)
a rule or body of rules of conduct inherent in human nature and essential to or binding upon human society
a rule or law concerning a natural phenomenon or the function of a complex system
"the principle of the conservation of mass"; "the principle of jet propulsion"; "the right-hand rule for inductive fields"
rule of personal conduct
(law) an explanation of the fundamental reasons (especially an explanation of the working of some device in terms of laws of nature)
"the rationale for capital punishment"; "the principles of internal-combustion engines"