bok choy vs crucifer

bok choy and crucifer both are nouns.

Word	Noun	Adjective	Verb	Adverb
bok choy	Yes	No	No	No
crucifer	Yes	No	No	No

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

bok choy: Asiatic plant grown for its cluster of edible white stalks with dark green leaves
crucifer: any of various plants of the family Cruciferae

Other hypernyms of bok choy include cruciferous plant.

bok choy (noun)	crucifer (noun)
elongated head of dark green leaves on thick white stalks	any of various plants of the family Cruciferae
Asiatic plant grown for its cluster of edible white stalks with dark green leaves