potato bean n 1: twining plant of Amazon basin having large edible roots [syn: yam bean, Pachyrhizus tuberosus] 2: a North American vine with fragrant blossoms and edible tubers; important food crop of Native Americans [syn: groundnut, groundnut vine, Indian potato, wild bean, Apios americana, Apios tuberosa] 3: nutlike tuber; important food of Native Americans [syn: groundnut, wild bean]