acidity vs tartness

acidity and tartness both are nouns.

Word	Noun	Adjective	Verb	Adverb
acidity	Yes	No	No	No
tartness	Yes	No	No	No

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

Other hyponyms of acidity include acerbity, vinegariness, vinegarishness.

As nouns, tartness is a hypernym of acidity; that is, tartness is a word with a broader meaning than acidity:

acidity: the taste experience when something acidic is taken into the mouth
tartness: the taste experience when vinegar or lemon juice is taken into the mouth

Other hypernyms of acidity include sour, sourness.

acidity (noun)	tartness (noun)
pH values below 7	a sharp sour taste
the property of being acidic	a rough and bitter manner
the taste experience when something acidic is taken into the mouth	the taste experience when vinegar or lemon juice is taken into the mouth