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]