bean vs bush bean

bean and bush bean both are nouns.

Word	Noun	Adjective	Verb	Adverb
bean	Yes	No	Yes	No
bush bean	Yes	No	No	No

As nouns, bush bean is a hyponym of bean; that is, bush bean is a word with a more specific, narrower meaning than bean:

bean: any of various leguminous plants grown for their edible seeds and pods
bush bean: a bean plant whose bushy growth needs no supports

Other hyponyms of bean include pole bean, shell bean, shell bean plant.

bean (noun)	bush bean (noun)
informal terms for a human head	a bean plant whose bushy growth needs no supports
any of various edible seeds of plants of the family Leguminosae used for food
any of various leguminous plants grown for their edible seeds and pods
any of various seeds or fruits that are beans or resemble beans

bean (verb)	bush bean (verb)
hit on the head, especially with a pitched baseball