While the military planned and operated many D-days during World War II, with most of them being landings on enemy-held coasts, it was in June 1944, during the invasion of Normandy, where the D-day term eventually became famous. The invasion of Normandy constituted the largest seaborne invasion in history, but it was also one of the most brutal missions. After getting delayed for several days due to poor weather, the troops of the Allied forces crossed the English Channel and arrived on the beaches of Normandy, France, on the morning of June 6. It was important to note that near the end of World War II, Normandy and the entire country of France was under the control of Nazi Germany, and the Allied Nations wanted to liberate France, but one of the few ways they can do that is by passing through the treacherous Omaha Beach.
Brutal fighting ensued on that day, with heavy losses on both sides. At the end of the mission, the Allied troops had taken hold of Omaha beach and the other nearby beaches, and the victory allowed them to have a firm foothold to march inland towards the east of France and eventually push the Nazi troops back to Germany. Despite being a critical Allied victory, the invasion of Normandy was followed by 11 more months of bloody conflict: Germany did not surrender until May 7, 1945.
Were There Other Letter-Days?
Besides D-day, the Allied forces have also used the term H-hour for shorter missions or shorter deadlines before the start of the operation. Similar to D-day, H-hour can also have numbers to indicate how many hours are left before the mission, and also how many hours have passed after the execution. Since the various Allied countries have different time zones, they would instead use D-day or H-hour to indicate how much time is remaining for preparation in the mission. Furthermore, the minus and plus days are also essential for military strategy, as it is during days like “D-3” or “D+2” that they can plan out what to do before or next and remember what they have planned by thinking about the indicated number.
There were also other letters that were placed before “-day.” The most memorable ones are L-day for Battle of Okinawa and A-day for Battle of Leyte. Today, the United States military has used all the letters of the alphabet to indicated specific days to commence plans, exercises, and operations. The military has used C-day for the commencement of a mission, E-day for NATO exercise missions, J-day to indicate the day where an assault happened, and V-day for the day they achieved victory. They have retired the use of certain letters like D and A to commemorate historical battles during World War II.
When Was D-Day First Used?
Although the term became popular in World War II, D-day has been in use since World War I. According to the US Center of Military History, the earliest recorded use of D-day was in a field order that was published on September 7, 1918, and in that order, it was indicated that the American Expeditionary Forces are going to evacuate the people of Saint-Mihiel Salient, France at “H-hour on D-day.”
What Does the Letter “D” in D-Day Stand For?
While some people believed that the “D” in D-day stands for something the US government knows, the truth is that the “D” stands for “day.” To put it simply, D-day means “day-day.” However, if you do add the numbers that indicated the days before or after the mission, like “D-4,” you can interpret this to mean “day minus 4.” The same can also be said for H-hour, as the H stands for “hour.”
D-Day (military term) (Wikipedia)
Normandy landings (Wikipedia)