Why was the allied invasion of Normandy known as D-Day?

Question: Why was the allied invasion of Normandy known as D-Day!?

What does the "D" in D-Day stand for!?Www@QuestionHome@Com

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Invasions were put on a timetable!. It would happen on "D"-day, at "H" hour, at "M" minute!. Operation Overload was the operation name, D-Day refers only to the day of invasion!. The operation lasted weeks!.Www@QuestionHome@Com

It wasn't!. The invasion of Normandy was Operation Overlord!. D-Day
literally refers only to the first day, 6/6/1944!. D-Day is a standard
military term which often denotes the time and date hostilities will
commence!. The "D" doesn't stand for anything specific!. It is
similar to "H-Hour" the exact time when a conflict is to begin!.
Again, the "H" isn't short for anything!.Www@QuestionHome@Com

The 'D' does not, in itself, officially stand for anything: it is there as a datum point that activates when the operation begins!.

Any large-scale military operation (anything involving more than about 100,000 men is usually large-scale, especially across water) requires a great deal of preparation: supply dumps have to be established, transportation allocated and routes and schedules worked out, troops and equipment assembled, specific training undertaken and completed, strategic and tactical reconnaissance undertaken and the results interpreted and utilised, etc!.

All of these activities take time, and need to be related to the operation under consideration!. Hence, food and ammunition have to be allocated from production schedules and accumulated in specific locations starting D minus two or three months (D-60 to D-90), specific training (beach landing and/or obstacle crossing, plus mission-specific requirements) take a minimum of six weeks, so must begin around D-50, allocation and assembly of shipping must be planned weeks or months in advance (shipping is used for other things, and bad planning means either idle shipping or NONE), so all of these various requirements down to loading warships or artillery for preliminary bombardments on D-3 and D-2 plus combat-loading the cargo ships on D-5 to D-1 have to be linked in and dovetailed with the date of the operation!.

If one were to do this planning and activity in terms of fixed calendar dates, then every time a proposed operation date was shifted, all the dates would have to be redone!. But if all planning dates are expressed relative to the operation itself, then the extensive documentation accompanying the operation planning does not need to be retyped each time a different date is considered!.

Naturally, the final choice of date for a major operation has to be settled weeks or months ahead of time: if the first activities have to begin on D-90, then one has to finalise the exact date at least three months ahead of execution!. When considering the Allied invasion of northern Europe, lead-time planning had to include deception schemes which would take months to implement (The 'US First Army Group', a simulated invasion near Calais to be observed by the one German radar station left operational for the purpose, etc!.), so decisions about the date of invasion in summer had to be taken in early spring!. The postponement from 5th to 6th June could be absorbed by holding all activities for one day, but a postponement to August would have required drastic reallocation of shipping which was already slated to carry supplies following the landings and created huge backlogs at ammunition dumps, etc!. not to mention the 'human factor' - the security risk of disembarking more than 80,000 fully-briefed men (and 20,000 plus airborne troops) who would have to be held in barracks incommunicado from their relatives for eight to ten weeks before conditions were right for an invasion again!.

So the 'D' has no official meaning: it is just a transferrable reference 'date' to which all other activities relevant to the operation are linked by relative time interval!.Www@QuestionHome@Com

The "D" stands for absolutly nothing!. It is simply a code, just like "walrus tango foxtrot" ?WTF!. I wonder why they gave such a massive invasion such a simple, short name :D :DWww@QuestionHome@Com

D stands for "Dooms Day" but Operation Overlord was the codename for the Allied invasion of northwest Europe!. The assault phase, or the establishment of a secure foothold, was known as Operation Neptune!. Operation Neptune began on D-Day (June 1, 1944) and ended on June 30, when the Allies had established a firm foothold in Normandy!. Operation Overlord also began on D-Day, and continued until Allied forces crossed the River Seine on August 19!.Www@QuestionHome@Com

D-Day means Doomsday!. It was Doomsday for the Nazis!. Only the first day of the Normandy invasion was known as D-Day, the full name was Operation Overlord!.Www@QuestionHome@Com

It was "Dooms" Day" (doomsday) for the Germans!.Www@QuestionHome@Com