diacritic vs macron

diacritic and macron both are nouns.

Word	Noun	Adjective	Verb	Adverb
diacritic	Yes	Yes	No	No
macron	Yes	No	No	No

As nouns, macron is a hyponym of diacritic; that is, macron is a word with a more specific, narrower meaning than diacritic:

diacritic: a mark added to a letter to indicate a special pronunciation
macron: a diacritical mark (-) placed above a vowel to indicate a long sound

Other hyponyms of diacritic include accent, accent mark, breve, cedilla, circumflex, hacek, wedge, tilde, umlaut, diaeresis, dieresis.

diacritic (noun)	macron (noun)
a mark added to a letter to indicate a special pronunciation	a diacritical mark (-) placed above a vowel to indicate a long sound

diacritic (adjective)	macron (adjective)
capable of distinguishing