butter bean vs butter-bean plant

butter bean and butter-bean plant both are nouns.

Word	Noun	Adjective	Verb	Adverb
butter bean	Yes	No	No	No
butter-bean plant	Yes	No	No	No

As nouns, butter bean and butter-bean plant are synonyms defined as:

butter bean and butter-bean plant: bush bean plant cultivated especially in southern United States having small flat edible seeds

Other synonyms of butter bean include lima bean, Phaseolus lunatus, sieva bean.

butter bean (noun)	butter-bean plant (noun)
small flat green bean similar to lima beans	bush bean plant cultivated especially in southern United States having small flat edible seeds
bush bean plant cultivated especially in southern United States having small flat edible seeds