On the morning of June 6, 1944, Allied forces staged an enormous assault on German positions on the beaches of Normandy, France. The invasion is often known by the famous nickname “D-Day,” yet few people know the origin of the term or what, if anything, the “D” stood for. Most argue it was merely a redundancy that also meant “day,” but others have proposed everything from “departure” to “decision” to “doomsday.”
Why D-Day Almost Never Happened
According to the U.S. military, “D-Day” was an Army designation used to indicate the start date for specific field operations. In this case, the “D” in D-Day doesn’t actually stand for anything—it’s merely an alliterative placeholder used to designate a particular day on the calendar.
On June 6, 1944, more than 156,000 American, British and Canadian troops stormed 50 miles of Normandy's fiercely defended beaches in northern France in an operation that proved to be a critical turning point in World War II.
Allied leaders Franklin D. Roosevelt and Winston Churchill knew from the start of the war that a massive invasion of mainland Europe would be critical to relieve pressure from the Soviet army fighting the Nazis in the east.
Since Operation Overlord was launched from England, the U.S. military had to ship 7 million tons of supplies to the staging area, including 450,000 tons of ammunition. Here, ammunition is shown in the town square of Morten-in-Marsh, England ahead of the invasion.
The D-Day invasion began in the pre-dawn hours of June 6 with thousands of paratroopers landing inland on the Utah and Sword beaches in an attempt to cut off exits and destroy bridges to slow Nazi reinforcements.
U.S. Army infantry men approaching Omaha Beach, Normandy, France on June 6, 1944. The first waves of American fighters were cut down in droves by German machine gun fire as they scrambled across the mine-riddled beach.
At Omaha Beach, U.S. forces persisted through the day-long slog, pushing forward to a fortified seawall and then up steep bluffs to take out the Nazi artillery posts by nightfall. Shown, wounded U.S. soldiers lean against chalk cliffs after storming Omaha Beach.
Anticipating an Allied invasion somewhere along the French coast, German forces had completed construction of the “Atlantic Wall,” a 2,400-mile line of bunkers, landmines and beach and water obstacles. Here, a land mine is blown up by Allied engineers.
Shown are massive landings at Omaha Beach after it was secured by U.S. troops. Barrage balloons keep watch overhead for German aircraft while scores of ships unload men and materials. D-Day was the largest amphibious invasion in military history. Less than a year later, on May 7, 1945, Germany would surrender.
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The military also employed the term “H-Hour” to refer to the time on D-Day when the action would begin. This shorthand helped prevent actual mission dates from falling into enemy hands, but it also proved handy when the start date for an attack was still undecided. Military planners also used a system of pluses and minuses to designate any time or day occurring before or after D-Day or H-Hour.
For example, D+2 meant two days after D-Day, while H-1 referred to one hour before H-Hour. These terms allowed units to effectively coordinate their operations ahead of time even when they didn’t know their actual start date, and they also provided flexibility in the event that the launch day shifted.
Use of these terms stretches back to World War I. One American field order from September 1918 noted, “The First Army will attack at H-Hour on D-Day with the object of forcing the evacuation of the St. Mihiel salient.” Other nations had their own shorthand. In World War I, the French used the code date “le Jour J,” while the British called their operation start days “Z-Day” and “Zero Hour.”
HISTORY Vault: D-Day in HD
HISTORY tells the story of D-Day in HD through rare footage rendered in high definition and interviews with the men who lived through it. Allied and German survivors tell their first-hand stories about the war that changed the course of the world.
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