The definition of a credo is a statement or system of beliefs or guiding principles.(noun)
Do unto others as you'd have them do unto you is an example of a credo.
See credo in Webster's New World College Dictionary
noun pl. credos
Origin: ME < L, I believe: see creed
See credo in American Heritage Dictionary 4
noun pl. cre·dos
Origin: Middle English, the Apostles' Creed
Origin: , from Latin crēdō, I believe (the first word of the Apostles' Creed or the Nicene Creed)
Origin: , first person sing. present tense of crēdere, to believe; see kerd- in Indo-European roots.
Learn more about credo