Principle, belief (5)
I believe the answer is:
tenet
I believe this is a double definition.
'principle' is the first definition.
(a tenet is a principle or value)
'belief' is the second definition.
(synonyms)
(Other definitions for tenet that I've seen before include "A belief or creed - a palindrome" , "Key principle" , "A palindromic doctrine or creed" , "Dogma or principle" , "Doctrine held to be true" .)