what does d stand for in d-day?

[D3ATH LORD]

im just loling my head off  

[Ad Bot]

[D3ATH LORD]

you mean it was dj people , the president was busy eating MARSHMALLOWS :)

[Niliscro]

From what I've learned, it has no specific meaning.  They didn't want to tell the troops involved when it actually was (to prevent information leaks), so they referred to it as "D-Day".  Only the high brass knew when it was.

Edit:
Spock's link explains it better though :\

[Visage]

It stands for day.

Yes, that means it's Day-day.

At least that's what I was told, although after a quick Google it seems it could stand for nothing.

He is actually right, it is day-day.

[brickybob]

D stands for an operation day, the day operation D happens.
In this case, the attack on the German bunker.

[Tom Gunn]

Dam-day

lol

[Thorax]

Day-of-Days is what I heard it meant.

[Sirrus]

It's an arbitrary letter* assigned to any day that an invasion takes place on.

That arbitrary letter is D. I can see how that might be interpreted as there can be other letters, such as F Day or Q Day.

[Oasis]

-Snip-

[Steamray]

Duel Day
Deathmatch Day  
Dog Day
Drum Day :P

[Darkhawk]

richard Day
Dong Day
Diggity Day
Damn Day
Dooms Day
DOAJDAJSLDKHA Day

[TapeDeck]

DingDong Day.

We rang Riddler's doorbell :]

[BladeOfTheHorizon]

Day of Defeat: Source

[blockland101]

its means Death-Day i think

[yoemex]

Day of Defeat: Source

lol day of defeat :D