meadow cress vs bittercress

meadow cress and bittercress both are nouns.

Word	Noun	Adjective	Verb	Adverb
meadow cress	Yes	No	No	No
bittercress	Yes	No	No	No

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

meadow cress: a bitter cress of Europe and America
bittercress: any of various herbs of the genus Cardamine, having usually pinnate leaves and racemes of white, pink or purple flowers; cosmopolitan except Antarctic

Other hypernyms of meadow cress include bitter cress.

meadow cress (noun)	bittercress (noun)
a bitter cress of Europe and America	any of various herbs of the genus Cardamine, having usually pinnate leaves and racemes of white, pink or purple flowers; cosmopolitan except Antarctic