nitroglycerin vs vasodilator

nitroglycerin and vasodilator both are nouns.

Word	Noun	Adjective	Verb	Adverb
nitroglycerin	Yes	No	No	No
vasodilator	Yes	No	No	No

As nouns, vasodilator is a hypernym of nitroglycerin; that is, vasodilator is a word with a broader meaning than nitroglycerin:

nitroglycerin: a heavy yellow poisonous oily explosive liquid obtained by nitrating glycerol; used in making explosives and medically as a vasodilator (trade names Nitrospan and Nitrostat)
vasodilator: a drug that causes dilation of blood vessels

Other hypernyms of nitroglycerin include vasodilative, nitrate.

nitroglycerin (noun)	vasodilator (noun)
a heavy yellow poisonous oily explosive liquid obtained by nitrating glycerol; used in making explosives and medically as a vasodilator (trade names Nitrospan and Nitrostat)	a drug that causes dilation of blood vessels