Source : Webster's Revised Unabridged Dictionary (1913)

Panama hat \Pan`a*ma" hat`\
   A fine plaited hat, made in Central America of the young
   leaves of a plant ({Carludovica palmata}).

Source : WordNet®

Panama hat
     n : a stiff straw hat with a flat crown [syn: {boater}, {leghorn},
          {Panama}, {sailor}, {skimmer}, {straw hat}]