dictum vs say-so

dictum and say-so both are nouns.

Word	Noun	Adjective	Verb	Adverb
dictum	Yes	No	No	No
say-so	Yes	No	No	No

As nouns, dictum and say-so are synonyms defined as:

Other synonyms of dictum include pronouncement.

dictum (noun)	say-so (noun)
an authoritative declaration	the power or right to give orders or make decisions
an opinion voiced by a judge on a point of law not directly bearing on the case in question and therefore not binding	an authoritative declaration
	one chap's arbitrary assertion