adiaphoron vs concept

adiaphoron and concept both are nouns.

Word	Noun	Adjective	Verb	Adverb
adiaphoron	Yes	No	No	No
concept	Yes	No	No	No

As nouns, concept is a hypernym of adiaphoron; that is, concept is a word with a broader meaning than adiaphoron:

adiaphoron: (Stoic philosophy) a matter having no moral merit or demerit.
concept: an abstract or general idea inferred or derived from specific instances

Other hypernyms of adiaphoron include conception, construct.

adiaphoron (noun)	concept (noun)
(Stoic philosophy) a matter having no moral merit or demerit.	an abstract or general idea inferred or derived from specific instances
a religious ceremonial or ritual observance that is held to be an affair of the individual conscience because it is neither forbidden nor enjoined by the scriptures.