Phaseolus lunatus vs butter bean

Phaseolus lunatus and butter bean both are nouns.

Word	Noun	Adjective	Verb	Adverb
Phaseolus lunatus	Yes	No	No	No
butter bean	Yes	No	No	No

As nouns, Phaseolus lunatus and butter bean are synonyms defined as:

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

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

Phaseolus lunatus (noun)	butter 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