butter-bean plant vs sieva bean

butter-bean plant and sieva bean both are nouns.

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

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

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

Other synonyms of butter-bean plant include butter bean, lima bean, Phaseolus lunatus.

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