acetum vs cider vinegar

acetum and cider vinegar both are nouns.

Word	Noun	Adjective	Verb	Adverb
acetum	Yes	No	No	No
cider vinegar	Yes	No	No	No

As nouns, cider vinegar is a hyponym of acetum; that is, cider vinegar is a word with a more specific, narrower meaning than acetum:

acetum: sour-tasting liquid produced usually by oxidation of the alcohol in wine or cider and used as a condiment or food preservative
cider vinegar: vinegar made from cider

Other hyponyms of acetum include chili vinegar, wine vinegar.

acetum (noun)	cider vinegar (noun)
sour-tasting liquid produced usually by oxidation of the alcohol in wine or cider and used as a condiment or food preservative	vinegar made from cider
a dilute solution of acetic acid that is used as a solvent (e.g. for a drug)