stone cress vs herb

stone cress and herb both are nouns.

Word	Noun	Adjective	Verb	Adverb
stone cress	Yes	No	No	No
herb	Yes	No	No	No

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

stone cress: any Old World herb of the genus Aethionema; native of sunny limestone habitats
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 stone cress include herbaceous plant.

stone cress (noun)	herb (noun)
any Old World herb of the genus Aethionema; native of sunny limestone habitats	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