poison vs hyoscyamine

poison and hyoscyamine both are nouns.

Word	Noun	Adjective	Verb	Adverb
poison	Yes	No	Yes	No
hyoscyamine	Yes	No	No	No

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

poison: any substance that causes injury or illness or death of a living organism
hyoscyamine: a poisonous crystalline alkaloid (isometric with atropine but more potent); used to treat excess motility of the gastrointestinal tract

Other hyponyms of poison include atropine, toxin, selenite.

poison (noun)	hyoscyamine (noun)
anything that harms or destroys	a poisonous crystalline alkaloid (isometric with atropine but more potent); used to treat excess motility of the gastrointestinal tract
any substance that causes injury or illness or death of a living organism