Source : WordNet®

yam bean
     n 1: twining plant of Amazon basin having large edible roots
          [syn: {potato bean}, {Pachyrhizus tuberosus}]
     2: Central American twining plant with edible roots and pods;
        large tubers are eaten raw or cooked especially when young
        and young pods must be thoroughly cooked; pods and seeds
        also yield rotenone and oils [syn: {Pachyrhizus erosus}]