"... In the military, D-Day is the day on which a combat attack or operation is to be initiated. The best known D-Day is June 6, 1944—the day of the Normandy landings—initiating the Western Allied effort to liberate mainland Europe from Nazi occupation during World War II. However, many other invasions and operations had a designated D-Day, both before and after that operation..".http://en.wikipedia.org/wiki/D-Day_%28military_term%29.
