Definition of H-hour in English:



  • The time of day at which an attack, landing, or other military operation is scheduled to begin.

    • ‘He will also be there with the troops in body armour and helmet minutes before H-hour - the moment the attack begins - when live ammunition is issued, to try to calm any last-minute nerves.’
    • ‘H-hour of 2359 would produce maximum surprise, making it difficult for enemy forces to mobilize to repel an invasion.’
    • ‘A compromise was reached and the H-hour was changed from 1800 hours to 1405 hours on 6 October.’
    • ‘Preplanned raids at specific H-hours typified the 4th ID's operations.’
    • ‘However, in the History of the War at Sea, the ships in the Western Task Force, opened fire at H-hour on D-day, an hour before those of us who were in the Eastern Task Force.’


World War I: from H (for hour) + hour.



/ˈāCH ˈˌou(ə)r/