Source : Webster's Revised Unabridged Dictionary (1913)

Cassava \Cas"sa*va\, n. [F. cassave, Sp. cazabe, fr. kasabi, in
   the language of Hayti.]
   1. (Bot.) A shrubby euphorbiaceous plant of the genus
      {Manihot}, with fleshy rootstocks yielding an edible
      starch; -- called also {manioc}.

   Note: There are two species, bitter and sweet, from which the
         cassava of commerce is prepared in the West Indies,
         tropical America, and Africa. The bitter ({Manihot
         utilissima}) is the more important; this has a
         poisonous sap, but by grating, pressing, and baking the
         root the poisonous qualities are removed. The sweet
         ({M. Aipi}) is used as a table vegetable.

   2. A nutritious starch obtained from the rootstocks of the
      cassava plant, used as food and in making tapioca.

Source : WordNet®

cassava
     n 1: a starch made by leaching and drying the root of the cassava
          plant; the source of tapioca; a staple food in the
          tropics [syn: {cassava starch}, {manioc}, {manioca}]
     2: cassava root eaten as a staple food after drying and
        leaching; source of tapioca [syn: {manioc}]
     3: any of several plants of the genus Manihot having fleshy
        roots yielding a nutritious starch [syn: {casava}]