Source : Webster's Revised Unabridged Dictionary (1913)

Blockade \Block*ade"\, n. [Cf. It. bloccata. See {Block}, v. t.
   ]
   1. The shutting up of a place by troops or ships, with the
      purpose of preventing ingress or egress, or the reception
      of supplies; as, the blockade of the ports of an enemy.

   Note: Blockade is now usually applied to an investment with
         ships or vessels, while siege is used of an investment
         by land forces. To constitute a blockade, the investing
         power must be able to apply its force to every point of
         practicable access, so as to render it dangerous to
         attempt to enter; and there is no blockade of that port
         where its force can not be brought to bear. --Kent.

   2. An obstruction to passage.

   {To raise a blockade}. See under {Raise}.

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.

   2. Hence, to shut in so as to prevent egress.

            Till storm and driving ice blockade him there.
                                                  --Wordsworth.

   3. To obstruct entrance to or egress from.

            Huge bales of British cloth blockade the door.
                                                  --Pope.

Source : WordNet®

blockade
     n 1: a war measure that isolates some area of importance to the
          enemy [syn: {encirclement}]
     2: prevents access or progress

blockade
     v 1: hinder or prevent the progress or accomplishment of; "His
          brother blocked him at every turn" [syn: {obstruct}, {block},
           {hinder}, {stymie}, {stymy}, {embarrass}]
     2: render unsuitable for passage; "block the way"; "barricade
        the streets"; "stop the busy road" [syn: {barricade}, {block},
         {stop}, {block off}, {block up}, {bar}]
     3: obstruct access to [syn: {block off}]
     4: impose a blockade on [syn: {seal off}]