D-day!
I always assumed D-day was derived from 'due day' or 'destruction day' or some such reasonable thing. I just found out today that the actual history of the word is far cooler (and maybe even stupider) than that. Here goes:
D-day
1918, "date set for the beginning of a military operation," with D as an abbreviation of day, cf. H-hour, also from the same military order of Sept. 7, 1918:
"The First Army will attack at H-Hour on D-Day with the object of forcing the evacuation of the St. Mihiel salient."
[Field Order No. 8, First Army, A.E.F.]
"They designate the day and hour of the operation when the day and hour have not yet been determined, or where secrecy is essential" [U.S. Army Center of Military History Web site]. Now almost exclusively of June 6, 1944.
for more, visit:
http://www.etymonline.com/index.php?l=d
D-day
1918, "date set for the beginning of a military operation," with D as an abbreviation of day, cf. H-hour, also from the same military order of Sept. 7, 1918:
"The First Army will attack at H-Hour on D-Day with the object of forcing the evacuation of the St. Mihiel salient."
[Field Order No. 8, First Army, A.E.F.]
"They designate the day and hour of the operation when the day and hour have not yet been determined, or where secrecy is essential" [U.S. Army Center of Military History Web site]. Now almost exclusively of June 6, 1944.
for more, visit:
http://www.etymonline.com/index.php?l=d