working rule vs working principle

working rule and working principle both are nouns.

Word	Noun	Adjective	Verb	Adverb
working rule	Yes	No	No	No
working principle	Yes	No	No	No

As nouns, working rule and working principle are synonyms defined as:

working rule and working principle: a rule that is adequate to permit work to be done

working rule (noun)	working principle (noun)
a rule that is adequate to permit work to be done	a rule that is adequate to permit work to be done