[1] : The Collaborative International Dictionary of English v.0.48

congestion \conges"tion\ ?; 106, n. l. congestio: cf. f.
   congestion.
   1. the act of gathering into a heap or mass; accumulation.
      obs.
      1913 webster

            the congestion of dead bodies one upon another.
                                                  --evelyn.
      1913 webster

   2. med. overfullness of the capillary and other blood
      vessels, etc., in any locality or organ often producing
      other morbid symptoms; local hyperaemia, active or
      passive; as, arterial congestion; venous congestion;
      congestion of the lungs.
      1913 webster

[2] : WordNet (r) 2.0

congestion
     n 1: excessive accumulation of blood or other fluid in a body
          part
     2: excessive crowding; "traffic congestion" syn: over-crowding
see also:
over-crowding 

[3] : Moby Thesaurus II by Grady Ward, 1.0

86 moby thesaurus words for "congestion":
   amplitude, bar, barrier, blank wall, blind alley, blind gut, block,
   blockade, blockage, bottleneck, cecum, choking, choking off, clog,
   closeness, compactness, congestedness, consistence, consistency,
   constipation, costiveness, crowdedness, cul-de-sac, dead end,
   denseness, density, embolism, embolus, engorgement, firmness,
   flood tide, full, fullness, gluiness, glut, gorge, hardness,
   high tide, high water, hyperemia, impasse, impediment,
   impenetrability, impermeability, impletion, imporosity,
   incompressibility, infarct, infarction, jam, jammedness, obstacle,
   obstipation, obstruction, overbrimming, overburden, overcharge,
   overflow, overfreight, overfullness, overload, overspill,
   overweight, plenitude, plethora, relative density, repletion,
   satiety, saturation, saturation point, sealing off, solidity,
   solidness, specific gravity, spissitude, spring tide, stop,
   stoppage, strangulation, supersaturation, surcharge, surfeit,
   thickness, viscidity, viscosity, viscousness

[4] : The Free On-line Dictionary of Computing (27 SEP 03)

congestion
     
        when the offered load of a data communication path exceeds the
        capacity.
     
     

Congestion >> C Words
Congestion, definition of term: Congestion
congestion_pag1.html