Don’t be alarmed the “D” in D-Day does not stand for doomsday it just stands for “day” if you don’t know what it is it’s. The Normandy landings were the landing operations and associated airborne operations on Tuesday, 6 June 1944 of the Allied invasion of Normandy in Operation Overlord during World War II. Codenamed Operation Neptune and often referred to as D-Day, it was the largest seaborne invasion in history.
In other words, the D in D-Day merely stands for Day. This coded designation was used for the day of any important invasion or military operation.