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

cofferdam \cof"ferdam\, n.
   a water-tight inclosure, as of piles packed with clay, from
   which the water is pumped to expose the bottom of a river,
   etc. and permit the laying of foundations, building of
   piers, etc.
   1913 webster

[2] : WordNet (r) 2.0

cofferdam
     n : large watertight chamber used for construction under water
         syn: caisson, pneumatic caisson
see also:
caisson pneumatic caisson 

Cofferdam >> C Words
Cofferdam, definition of term: Cofferdam
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