principle

Noun

• (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
    

• rule of personal conduct

• 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
    

• a basic truth or law or assumption
  • the principles of democracy
    

• a rule or standard especially of good behavior
  • a man of principle
    
  • he will not violate his principles
    

• 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
    

Related words

• Synonyms: 
  rationale , precept , rule