pasturage vs herb

pasturage and herb both are nouns.

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

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

pasturage: succulent herbaceous vegetation of pastureland
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 pasturage include herbaceous plant.

pasturage (noun)	herb (noun)
bulky food like grass or hay for browsing or grazing horses or cattle	aromatic potherb used in cookery for its savory qualities
succulent herbaceous vegetation of pastureland	a plant lacking a permanent woody stem; many are flowering garden plants or potherbs; some having medicinal properties; some are pests