[Ads-l] "H-Hour" and "J-Day", 21 Feb 1918

[ADSGarson O'Toole]

Excellent work, Peter.
Garson

On Sun, Jun 8, 2025 at 5:33 PM Peter Reitan <pjreitan at hotmail.com> wrote:
>
> There was some discussion of "J-Day" and "H-Hour" here last month.  The competing theories were "J" from the French Jour and "J" in reference to "jumping off," a common military term at the time for the moment or place of launching an attack.
>
> I thought that jumping off seems unlikely, since it would be ambiguous - as there would be a jumping off day and a jumping off hour.  Not impossible, I suppose, but it seem logically inconsistent.
>
> Dave Wilton put together a summary of some of the early references in a post.
> https://wordorigins-org.ghost.io/d-day-h-hour-j-day/
>
> I've since done some wading through US, French and British military and historical references which suggest to me that the French likely used "Jour-J" first, which influenced the US to use "D-Day," after using "J-Day" for a brief period of time.  The British used "Z-Day" for Zero Day, for the day of the attack, and "Zero Hour" for the moment of the attack during the same period.

------------------------------------------------------------
The American Dialect Society - http://www.americandialect.org