The Collaborative International Dictionary of English v.0.48:

Seine \Seine\, n. [F. seine, or AS. segene, b?th fr. L. sagena,
   Gr. ????.] (Fishing.)
   A large net, one edge of which is provided with sinkers, and
   the other with floats. It hangs vertically in the water, and
   when its ends are brought together or drawn ashore incloses
   the fish.
   [1913 Webster]

   Seine boat, a boat specially constructed to carry and pay
      out a seine.
      [1913 Webster]