diacritic vs tilde

diacritic and tilde both are nouns.

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

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

diacritic: a mark added to a letter to indicate a special pronunciation
tilde: a diacritical mark (~) placed over the letter n in Spanish to indicate a palatal nasal sound or over a vowel in Portuguese to indicate nasalization

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

diacritic (noun)	tilde (noun)
a mark added to a letter to indicate a special pronunciation	a diacritical mark (~) placed over the letter n in Spanish to indicate a palatal nasal sound or over a vowel in Portuguese to indicate nasalization

diacritic (adjective)	tilde (adjective)
capable of distinguishing