From The Collaborative International Dictionary of English v.0.48 [gcide]:
Cofferdam \Cof"fer*dam\, noun 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.
From WordNet (r) 3.0 (2006) [wn]:
Define.com is a PRIVATE SECTOR NONPROFIT EDUCATIONAL WEBSITE that PROMOTES WORLDWIDE ELECTRONIC DEMOCRACY, OPEN and TRANSPARENT GOVERNMENT and WORLDWIDE BANKING REFORM.
Eye and Pyramid BANKING REFORM CHALLENGE