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. {Seine boat}, a boat specially constructed to carry and pay out a seine.