Tell me about the D in D-Day.
5 minutes | D-Day | Decision Day | Eisenhower | TIME MagazineWhenever someone says ‘D-Day’, I do get an urge to say, “which-which, D-Day-D are you talk-talking about?
There were many D-Days during the Second World War. None of the abbreviated forms were shorthand for Decision Day, Doomsday, Dreadnought Day, Die-Hard Day or any other version of an alliterative fronted adverbial. The ‘D-Day’ designation was used liberally throughout, simply to designate a proposed day on which an invasion or important military operation would commence. I’ll say this more than once: ‘D-Day’ is shorthand for Day-Day, which drives, me, nuts.
In this instance— 6th June, 1944, the day our eponymous ‘D-Day’ became enshrined in memory as a definitive 24-hour period— the offensive action was Operation OVERLORD. American, Canadian, and British troops set out for five beaches in Normandy, code-named SWORD, JUNO, GOLD, OMAHA and UTAH. That was June.


Southwick House was drenched the next morning, so a sea-crossing in those conditions would have done untold damage to our forces. Instead, first thing on the 5th, he canvassed the opinions of each man at the table as to their views on an assault for the 6th June.
Montgomery, leading the assault forces, agreed it should be 6th June. Ramsay, naval Commander in Chief, said it should be 6th June. Air Chief Marshal Sir Trafford Leigh-Mallory passed his judgement— the 6th June— and so it came to pass. D-Day would be, er, D-Day. But those are the facts. Let’s get back to the fiction.

In fact, many of Eisenhower’s verbatim comments weren’t recorded with the level of detail that historians appreciate today— certainly not in the same way we have a corpus of Churchillian rhetoric. Self-promotion wasn’t Ike’s style. Still, in his book The Longest Day: The Classic Epic of D-Day, Cornelius Ryan wrote:
“Apart from the four stars of his rank, a single ribbon of decorations above his breast pocket and the flaming shoulder patch of SHAEF (Supreme Headquarters Allied Expeditionary Force), Eisenhower shunned all distinguishing marks. Even in the trailer there was little evidence of his authority: no flags, maps, framed directives, or signed photographs of the great or neargreats who visited him.”
Does that sound like someone who would have asked his executive assistant to clarify the minutiae of a definition with an explanation that wouldn’t stand up to scrutiny? Not really.
Another notion comes from Paul Dickson’s rationale, in his book War Slang: American Fighting Words and Phrases Since the Civil War— a great book for myriad reasons, the least of which is the fact that Dickson cited sources he believed worthy of credit. Dickson writes:
“The French maintain the D means ‘disembarkation’, still others say ‘debarkation’, and the more poetic insist D-Day is short for ‘day of decision’.”
More recently, for TIME Magazine in 2019, Dickson doubles-down:
“I think ‘disembarkation’ makes more sense because it was an amphibious assault. There was a point in 1940 when they started putting together an army and they had a first draft in anticipation of the Second World War, called M-Day, with the ‘M’ standing for ‘mobilization’. In addition, men in the U.S. between 21 and 35 had to register for the draft on Oct. 16, 1940—which was referred to as R-Day, or ‘registration day’. It was common military parlance, just give something a letter.”
Well yes, but then again, perhaps no. Surely the best time to ask a question, is when the answer is readily available? I believe TIME Magazine itself provided the most reasonable answer. Six days after the event, with little time to fictionalise, this appeared in the letters section of their June 12th issue, 1944:
Sirs:
Everybody refers to D-Day, H-Hour. Can you please tell me what they stand for or how they originated?
(NAME WITHHELD BY REQUEST), Toronto
“D for Day, H for Hour means the undetermined (or secret) day and hour for the start of a military operation. Their use permits the entire timetable for the operation to be scheduled in detail and its various steps prepared by subordinate commanders long before a definite day and time for the attack have been set. When the day and time are fixed, subordinates are so informed.
So far as the U.S. Army can determine, the first use of D for Day, H for Hour was in Field Order No. 8, of the First Army, A.E.F., issued on Sept. 7, 1918, which read: “The First Army will attack at H–Hour on D-Day with the object of forcing the evacuation of the St. Mihiel salient.”—ED.
So, D-Day does means Day-Day, after all. 🤦♀️