cow parsnip vs herb

cow parsnip and herb both are nouns.

Word	Noun	Adjective	Verb	Adverb
cow parsnip	Yes	No	No	No
herb	Yes	No	No	No

As nouns, herb is a hypernym of cow parsnip; that is, herb is a word with a broader meaning than cow parsnip:

cow parsnip: tall coarse plant having thick stems and cluster of white to purple flowers
herb: a plant lacking a permanent woody stem; many are flowering garden plants or potherbs; some having medicinal properties; some are pests

Other hypernyms of cow parsnip include herbaceous plant.

cow parsnip (noun)	herb (noun)
tall coarse plant having thick stems and cluster of white to purple flowers	aromatic potherb used in cookery for its savory qualities
	a plant lacking a permanent woody stem; many are flowering garden plants or potherbs; some having medicinal properties; some are pests