The Collaborative International Dictionary of English v.0.48:

Taro \Ta"ro\, n. [From the Polynesian name.] (Bot.)
   A name for several aroid plants (Colocasia antiquorum, var.
   esculenta, Colocasia macrorhiza, etc.), and their
   rootstocks. They have large ovate-sagittate leaves and large
   fleshy tuberous rootstocks, which are cooked and used for
   food in tropical countries.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Colocasia \Colocasia\ n.
   a small genus of perennial tuberous herbs of the arum family,
   of tropical Asia and the Pacific islands, including the
   taro (Colocasia esculente).

   Syn: genus Colocasia.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

taro
    n 1: edible starchy tuberous root of taro plants [syn: taro,
         cocoyam, dasheen, eddo]
    2: herb of the Pacific islands grown throughout the tropics for
       its edible root and in temperate areas as an ornamental for
       its large glossy leaves [syn: taro, taro plant, dalo,
       dasheen, Colocasia esculenta]
    3: tropical starchy tuberous root [syn: taro, taro root,
       cocoyam, dasheen, edda]