sieva bean vs butter-bean plant

sieva bean and butter-bean plant both are nouns.

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

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

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

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

sieva 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