D-Day 2024 is on Thursday, June 6, 2024: Day - Why was D-Day called that?

Thursday, June 6, 2024 is D-Day 2024. The Normandy landings, codenamed Operation Neptune, were the landing operations of the Allied invasion of Normandy, in Operation Overlord, during World War II.

The Normandy landings, codenamed Operation Neptune, were the landing operations of the Allied invasion of Normandy, in Operation Overlord, during World War II.

In the military, D-Day is the day on which a combat attack or operation is to be initiated. The best known D-Day is June 6, 1944 — the day of the Normandy landings — initiating the Western Allied effort to liberate mainland Europe from Nazi occupation during World War II.

Dictionary: D-day

The unnamed day on which an operation or offensive is to be launched.

The day on which the Allied forces invaded France during World War II (June 6, 1944).

[D (abbr. of DAY) + DAY.]

Word Origin: D-Day

Origin: 1918

The Yanks were coming! In April 1917, after three years of the Great War that was consuming Europe, we abandoned our neutrality and declared war on Germany, the country we saw as the aggressor. By June of that year, the first units of the American Expeditionary Force reached the battlefields of France. The A.E.F. provided much assistance to the French and British, and victory was achieved and an armistice declared the next year, on the eleventh day of the eleventh month of 1918.

Because we were last on the battlefield, most of the military vocabulary added to our language during World War I came from the British, like the name of the new military vehicle the tank. But apparently it was the Americans who contributed a technical term that would become famous a quarter of a century later, during World War II. Field Order No. 8 from the First Army of the A.E.F., of September 7, 1918, begins, "the First Army will attack at H-Hour on D-Day with the object of forcing the evacuation of the St. Mihiel salient."

The British used zero hour in discussion of an operation whose time was not yet determined or to be kept secret, but Americans preferred H-Hour and D-Day. In the next World War, with American general Dwight Eisenhower in supreme command, the term for the first day of the Allied invasion of France, June 6, 1944, was the American D-Day. That D-Day was and is so famous that it successfully invaded our general vocabulary to become a term that can refer to any day of action or decision. Other letters were combined with Day to give similar emphasis to a particular day, such as V-E Day and V-J Day for the 1945 endings of the war in Europe and Japan, respectively, and E Day for "Education Day" (also attested as early as 1945).

US Military History Companion: D‐Day Landing (1944)

Operation Overlord was the greatest amphibious attack in history. Nearly 175,000 American, Canadian, and British troops landed in Normandy on D‐Day, 6 June 1944, supported by 6,000 aircraft and 6,000 naval vessels ranging in size from battleships to 32‐foot landing craft. The object of the attack was to win a beachhead in France in order to open a second front against Hitler's armies and to use the beachhead as a springboard for the liberation of France and Belgium, and the eventual conquest of Nazi Germany.

Planning began in earnest early in 1943. The critical need for the Allies was to gain surprise, because they would be taking the offensive with nine divisions, none armored, against an enemy with fifty‐five divisions in France, nine of them armored. Gen. Gerd von Rundstedt, commanding the German forces in the west, and Gen. Erwin Rommel, commanding the forces in France, assumed that the Allies would have to gain a major port in the initial assault, so they strengthened the “Atlantic Wall” around the French ports, especially Calais, which was on the direct line London‐Dover‐Calais‐Belgium‐Cologne‐Berlin. The Allied supreme commander, Gen. Dwight D. Eisenhower, achieved surprise by attacking straight south rather than east, and by going ashore in Normandy, where there were no significant ports. An elaborate and highly successful deception plan (Operation Fortitude) kept the German attention centered on Calais.

Britannica Concise Encyclopedia: D-Day

In U.S. military history, any designated day for the commencement of a major operation. The designation apparently originated in World War I; its meaning is uncertain, though it is probable that the "D" stands for nothing more than "Day." (The designated time for commencement of action on any D-Day was referred to as H-Hour.) The most celebrated D-Day occurred on June 6, 1944, the first day of the Anglo-American invasion of Europe in World War II. See Normandy Campaign.

US History Encyclopedia: D Day

The term "D Day" indicates the beginning of an attack or other military operation when the specific date has yet to be selected or secrecy is required. "H Hour" is similarly used to designate the time of the attack.

The "D" and "H" are derived from the first letters of "day" and "hour." There is one D Day and H Hour for all units participating in an operation. Plus and minus signs are used to indicate the number of days or hours that precede or follow the specific operation. Thus, 舑5 means five days before D Day and H + 2 means two hours after H Hour.

Planning for operations can begin months before the anticipated time of the operation. The use of D Day minus "X number of days" signifies the date by which certain actions, such as planning or the training of units, must be complete. At the appropriate time an order is published giving a specific date for D Day.

The U.S. Army first used the term on 7 September 1918, when it issued First Army Field Order Number 9: "The First Army will attack at H Hour on D Day with the object of forcing the evacuation of the St. Mihiel Salient." The term is most commonly associated with the invasion of Normandy on 6 June 1944.

History Dictionary: D-Day

The code name for the first day of a military attack, especially the American and British invasion of German-occupied France during World War II on June 6, 1944 (see invasion of Normandy). This marked the beginning of the victory of the Allies in Europe. Germany surrendered less than a year later.

Abbreviations: D-DAY

is short for:

(beginning Of Contingency Operation Or Of Hostilities)

Wikipedia: D-Day

D-Day is a term often used in military parlance to denote the day on which a combat attack or operation is to be initiated. "D-Day" often represents a variable, designating the day upon which some significant event will occur or has occurred; see Military designation of days and hours for similar terms. The initial D in D-Day has had various meanings in the past, while more recently it has obtained the connotation of "Day" itself, thereby creating the phrase "Day-Day".[1]

By far, the best known D-Day is June 6, 1944 — the day on which the Battle of Normandy began — commencing the Western Allied effort to liberate mainland Europe from Nazi occupation during World War II. However, many other invasions and operations had a designated D-Day, both before and after Operation Overlord.

The terms D-Day and H-Hour are used for the day and hour on which a combat attack or operation is to be initiated. They designate the day and hour of the operation when the day and hour have not yet been determined, or where secrecy is essential. There is but one D-Day and one H-Hour for all units participating in a given operation.

When used in combination with figures, and plus or minus signs, these terms indicate the point of time preceding or following a specific action. Thus, H−3 means 3 hours before H-Hour, and D+3 means 3 days after D-Day. H+75 minutes means H-Hour plus 1 hour and 15 minutes.

Planning papers for large-scale operations are made up in detail long before specific dates are set. Thus, orders are issued for the various steps to be carried out on the D-Day or H-Hour minus or plus a certain number of days, hours, or minutes. At the appropriate time, a subsequent order is issued that states the actual day and times.

The earliest use of these terms by the U.S. Army that the Center of Military History has been able to find was during World War I. In Field Order Number 9, First Army, American Expeditionary Forces, dated 7 September 1918: "The First Army will attack at H hour on D day with the object of forcing the evacuation of the St. Mihiel Salient."

D-Day for the invasion of Normandy by the Allies was originally set for 5 June 1944, but bad weather and heavy seas caused Gen. Dwight D Eisenhower to delay until 6 June and that date has been popularly referred to ever since by the short title "D-Day". (In French, it is called Le Jour J or, occasionally, Le Choc.) Because of this, planners of later military operations sometimes avoided the term. For example, Douglas MacArthur's invasion of Leyte began on "A-Day", and the invasion of Okinawa began on "L-Day". The Allies proposed invasions of Japan that would have begun on "X-Day" (Kyūshū, scheduled for November 1945) and "Y-Day" (Honshū, scheduled for March 1946).

What is D-Day?

By far, the best known D-Day is June 6, 1944 — the day on which the Invasion of Normandy began — commencing the Western Allied effort to liberate mainland Europe from Nazi occupation during World War II. However, many other invasions and operations had a designated D-Day, both before and after that operation.

D-Day for the invasion of Normandy by the Allies was originally set for 5 June 1944, but bad weather and heavy seas caused Gen. Dwight D Eisenhower to delay until June 6 and that date has been popularly referred to ever since by the short title "D-Day". (In French, it is called Le Jour J or, occasionally, Le Choc.) Because of this, planners of later military operations sometimes avoided the term. For example, Douglas MacArthur's invasion of Leyte began on "A-Day", and the invasion of Okinawa began on "L-Day". The Allies proposed invasions of Japan that would have begun on "X-Day" (Kyūshū, scheduled for November 1945) and "Y-Day" (Honshū, scheduled for March 1946).

What exactly is D-Day?

D-day is a generic term meaning the day a military operation is scheduled to start. The hour the operation is scheduled to start is generically "H-Hour." This allows for planning without knowing exactly when the operation will be put into effect, and without risking a leak of the exact day and time of an operation.

There have been many D-days, often, but not always associated with an amphibeous invasion or attack. However, the most famous D-Day and the one you might be thinking of, was June 6, 1944, when the combined forces of the United States, Great Britain, the British Commonwealth and the Free French Army landed on the beaches of Normandy, france, thus breaching Hitler's Atlantic Fortress.