- The time of day at which an attack, landing, or other military operation is scheduled to begin: they assured the Marines that at H-hour the reef would be covered by five feet of waterMore example sentences
- Preplanned raids at specific H-hours typified the 4th ID's operations.
- 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.
First World War: from H (for hour) + hour.
More definitions of H-hourDefinition of H-hour in:
- The US English dictionary