a rule or body of rules of conduct inherent in human nature and essential to or binding upon human society

a guiding principle

principles from which other truths can be derived

the principles that guide reasoning within a given field or situation

(psychoanalysis) the governing principle of the id; the principle that an infant seeks gratification and fails to distinguish fantasy from reality

(psychoanalysis) the governing principle of the ego; the principle that as a child grows it becomes aware of the real environment and the need to accommodate to it