green bean vs common bean plant

green bean and common bean plant both are nouns.

Word	Noun	Adjective	Verb	Adverb
green bean	Yes	No	No	No
common bean plant	Yes	No	No	No

As nouns, common bean plant is a hypernym of green bean; that is, common bean plant is a word with a broader meaning than green bean:

green bean: a common bean plant cultivated for its slender green edible pods
common bean plant: the common annual twining or bushy bean plant grown for its edible seeds or pods

Other hypernyms of green bean include common bean, Phaseolus vulgaris.

green bean (noun)	common bean plant (noun)
immature bean pod eaten as a vegetable	the common annual twining or bushy bean plant grown for its edible seeds or pods
seed of the mung bean plant used for food; food from the seed of the mung bean plant
a common bean plant cultivated for its slender green edible pods
seed of the mung bean plant; used for food; seed of the mung bean plant