digitalis vs herb

digitalis and herb both are nouns.

Word	Noun	Adjective	Verb	Adverb
digitalis	Yes	No	No	No
herb	Yes	No	No	No

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

digitalis: any of several plants of the genus Digitalis
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 digitalis include herbaceous plant.

digitalis (noun)	herb (noun)
any of several plants of the genus Digitalis	aromatic potherb used in cookery for its savory qualities
a powerful cardiac stimulant obtained from foxglove	a plant lacking a permanent woody stem; many are flowering garden plants or potherbs; some having medicinal properties; some are pests