Blockading

from WordNet (r) 3.0 (2006)

blockading
    adj 1: blocking entrance to and exit from seaports and harbors;
           "the blockading ships prevented delivery of munitions"

from The Collaborative International Dictionary of English v.0.48

Blockade \Block*ade"\, v. t. [imp. & p. p. {Blockaded}; p. pr. &
   vb. n. {Blockading}.]
   1. To shut up, as a town or fortress, by investing it with
      troops or vessels or war for the purpose of preventing
      ingress or egress, or the introduction of supplies. See
      note under {Blockade}, n. "Blockaded the place by sea."
      --Gilpin.
      [1913 Webster]

   2. Hence, to shut in so as to prevent egress.
      [1913 Webster]

            Till storm and driving ice blockade him there.
                                                  --Wordsworth.
      [1913 Webster]

   3. To obstruct entrance to or egress from.
      [1913 Webster]

            Huge bales of British cloth blockade the door.
                                                  --Pope.
      [1913 Webster]