zerofay32
Buckeye
...D. Day (Day of Deliverance)...
D-day and H-hour were standard military terms used to describe the day and hour that an operation would start and dates back to WWI. There were actually several "D-days" during WWII before Operation Overlord. After Overlord, the general public became aware of the term and calling the start of the Normandy Campaign as D-Day became commonplace. To avoid confusion, the military began using other designations. (A-Day, L-Day, X-Day).