Idiom (8)
'idiom' is the definition.
(synonyms)
This is all the clue.
(Other definitions for parlance that I've seen before include "Way of using words" , "Manner of speaking peculiar to a specific group" , "Earn clap for vocabulary of particular subject" , "Idiom" , "Conversation" .)
(Other definitions for axiom that I've seen before include "Self-evident principle" , "that's self-evident" , "Self-evident statement" , "Maxim, self-evident truth" , "Principle; assumption" .)