The Collaborative International Dictionary of English v.0.48:

Canna \Can"na\, n. [L., a reed. See Cane.] (Bot.)
   A genus of tropical plants, with large leaves and often with
   showy flowers. The Indian shot (Canna Indica) is found in
   gardens of the northern United States.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Canna \Can"na\, n. [It.]
   A measure of length in Italy, varying from six to seven feet.
   See Cane, 4.
   [1913 Webster]

WordNet (r) 3.0 (2006):

canna
    n 1: any plant of the genus Canna having large sheathing leaves
         and clusters of large showy flowers