In naval architecture, a flush deck refers to when the upper deck of a vessel extends unbroken from stem to stern. There is no raised forecastle or lowered quarterdeck. Ships of this type may be referred to as "flush deckers", although this is often taken as referring to a series of United States Navy destroyers originating from World War I and typified by the Wickes class. For aircraft carriers it means that no "island" superstructure was fitted.
The original article can be found at Flush deck and the edit history here.