The meaning behind the "D" in D-Day has to do with military terminology. On the morning of June 6, 1944, Allied forces staged an enormous assault on German positions on the beaches of Normandy, France. The invasion is often known by the famous nickname “D-Day,” yet few people know the origin of the term or what, if anything, the “D” stood for. Most argue it was merely a redundancy that also meant “day,” but others have proposed everything from “departure” to “decision” to “doomsday.” According to the U.S. military, “D-Day” was an Army designation used to indicate the start date...