kohlrabi vs crucifer

kohlrabi and crucifer both are nouns.

Word	Noun	Adjective	Verb	Adverb
kohlrabi	Yes	No	No	No
crucifer	Yes	No	No	No

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

kohlrabi: plant cultivated for its enlarged fleshy turnip-shaped edible stem
crucifer: any of various plants of the family Cruciferae

Other hypernyms of kohlrabi include cruciferous plant.

kohlrabi (noun)	crucifer (noun)
fleshy turnip-shaped edible stem of the kohlrabi plant	any of various plants of the family Cruciferae
plant cultivated for its enlarged fleshy turnip-shaped edible stem