Source : Webster's Revised Unabridged Dictionary (1913)

Blockage \Block"age\, n.
   The act of blocking up; the state of being blocked up.

Source : WordNet®

blockage
     n 1: the state or condition of being obstructed [syn: {obstruction}]
     2: an obstruction in a pipe or tube; "we had to call a plumber
        to clear out the blockage in the drainpipe" [syn: {block},
         {closure}, {occlusion}, {stop}, {stoppage}]
     3: the act of blocking [syn: {closure}, {occlusion}]