waterleaf vs herb

waterleaf and herb both are nouns.

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

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

waterleaf: any of several plants of the genus Hydrophyllum
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 waterleaf include herbaceous plant.

waterleaf (noun)	herb (noun)
any of several plants of the genus Hydrophyllum	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