cultivated cabbage vs crucifer

cultivated cabbage and crucifer both are nouns.

Word	Noun	Adjective	Verb	Adverb
cultivated cabbage	Yes	No	No	No
crucifer	Yes	No	No	No

As nouns, crucifer is a hypernym of cultivated cabbage; that is, crucifer is a word with a broader meaning than cultivated cabbage:

cultivated cabbage: any of various cultivars of the genus Brassica oleracea grown for their edible leaves or flowers
crucifer: any of various plants of the family Cruciferae

Other hypernyms of cultivated cabbage include cruciferous plant.

cultivated cabbage (noun)	crucifer (noun)
any of various cultivars of the genus Brassica oleracea grown for their edible leaves or flowers	any of various plants of the family Cruciferae