sieva bean vs butterbean

sieva bean and butterbean both are nouns.

Word	Noun	Adjective	Verb	Adverb
sieva bean	Yes	No	No	No
butterbean	Yes	No	No	No

As nouns, sieva bean and butterbean are synonyms defined as:

Other synonyms of sieva bean include butter bean, civet bean.

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