yam

yam
    n 1: edible tuber of any of several yams
    2: any of a number of tropical vines of the genus Dioscorea many
       having edible tuberous roots [syn: {yam}, {yam plant}]
    3: sweet potato with deep orange flesh that remains moist when
       baked
    4: edible tuberous root of various yam plants of the genus
       Dioscorea grown in the tropics world-wide for food
    

Yam \Yam\ (y[a^]m), n. [Pg. inhame, probably from some native
   name.]
   1. (Bot.) A large, esculent, farinaceous tuber of various
      climbing plants of the genus {Dioscorea}; also, the plants
      themselves. Mostly natives of warm climates. The plants
      have netted-veined, petioled leaves, and pods with three
      broad wings. The commonest species is {Dioscorea sativa},
      but several others are cultivated.
      [1913 Webster]

   2. (Bot.) Any one of several cultural varieties of the sweet
      potato. [U. S.]
      [Webster 1913 Suppl.]

   {Chinese yam}, a plant ({Dioscorea Batatas}) with a long and
      slender tuber, hardier than most of the other species.

   {Wild yam}.
      (a) A common plant ({Dioscorea villosa}) of the Eastern
          United States, having a hard and knotty rootstock.
      (b) An orchidaceous plant ({Gastrodia sesamoides}) of
          Australia and Tasmania.
          [1913 Webster]