Wordnet 3.0
NOUN (2)
1. 
 the principles of right and wrong that are accepted by an individual or a social group; 
- Example: "the Puritan ethic"- Example: "a person with old-fashioned values"[syn: ethic, moral principle, value-system, value orientation]
2.  the principle that conduct should be moral; 
WordNet (r) 3.0 (2006):
moral principle
    n 1: the principles of right and wrong that are accepted by an
         individual or a social group; "the Puritan ethic"; "a
         person with old-fashioned values" [syn: ethic, moral
         principle, value-system, value orientation]
    2: the principle that conduct should be moral