What does the “D” in “D Day” mean? And now, the “A” in “A” Day?
http://boards.straightdope.com/sdmb/showthread.php?threadid=48888&highlight=dday
It stands for “day”.
For the present conflict, the A in A-Day meant the day the air assault was to begin. G-Day was to be the day th ground assault began. Things changed at the last minute and they were pretty much reversed.
I don’t know about the D in D-Day.
S-Day is when Special Forces operations begin. So for Iraq, the war plan was S-Day, G-Day, A-Day. According to Tommy Franks this was the plan all along and was not changed by the initial air attack on the “target of opportunity”.
Heh. I’m just not keeping up.
During the planning stages for Operation Overlord, the invasion of Normandy, the date and time of the invasion had not been fixed. The plans referred to the day as D , and the hour as H.
Therefor, as Mahaloth has said, it stands for Day. The press picked up the term, and it has been synonymous with June 6 ever since.
The use of “D” and “H” predates June 6 in planning. Such operations have to be planned far in advance, well before the exact date and hour can be known. In fact, until the plans have been pretty well completed you are never sure of just what forces and materiel will be required so you can’t know how long it is going to take you to get ready.
Therefore, planners of all kinds set the time line by things like “H minus 8 hours the Underwater Demolition group will start toward the beach”, “D minus 5, troops will begin assembly at the port staging areas”, “D minus 60, all needed assault forces and reinforcements will be available” and so on.
In planning what you want to happen before and after the beginning of an operation, you don’t always know exactly WHEN it is going to start. You designate the launch of the attack as “H-Hour” on “D-Day” so that you can plan what is needed to be done on “D minus 3” or “D plus 5”. For instance, at “H minus 6” you want to blow the minefields in your way, and “H minus 2” everyone is awake, fed, armed, and in line. By “D plus 3” you may plan to have certain objectives secured. All without knowing what time or what day everything is going down. Then when the decision is made, all those D’s and H’s can be translated into actual dates and times, but what really matters is how those dates and times relate to the moment it all begins.
Or what he said.