costmary vs herb

costmary and herb both are nouns.

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

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

costmary: leaves used sparingly (because of bitter overtones) in sauces and soups and stuffings
herb: aromatic potherb used in cookery for its savory qualities

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

costmary: tansy-scented Eurasian perennial herb with buttonlike yellow flowers; used as potherb or salad green and sometimes for potpourri or tea or flavoring; sometimes placed in genus Chrysanthemum
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 costmary include herbaceous plant.

costmary (noun)	herb (noun)
leaves used sparingly (because of bitter overtones) in sauces and soups and stuffings	aromatic potherb used in cookery for its savory qualities
tansy-scented Eurasian perennial herb with buttonlike yellow flowers; used as potherb or salad green and sometimes for potpourri or tea or flavoring; sometimes placed in genus Chrysanthemum	a plant lacking a permanent woody stem; many are flowering garden plants or potherbs; some having medicinal properties; some are pests