WordNet (r) 3.0 (2006):

potato bean
    n 1: twining plant of Amazon basin having large edible roots
         [syn: yam bean, potato 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, potato
       bean, wild bean, Apios americana, Apios tuberosa]
    3: nutlike tuber; important food of Native Americans [syn:
       groundnut, potato bean, wild bean]