Definition
The exact time an operation or attack is scheduled to commence. Missing zero hour is a great way to ensure your carefully planned assault becomes a very expensive camping trip.
Example Usage
All units will cross the line of departure at zero hour, which is 0400 local time.
Origin
World War I terminology, from the practice of synchronizing watches and counting down to H-Hour (the hour) and zero minute (the exact moment)
Fun Fact
The term spawned numerous variations including H-Hour, D-Day, and the phrase 'eleventh hour' for last-minute timing.
Source: Traditional military operations terminology
Related Terms
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See “zero hour” in Corporate Speak, Gen-Z Slang, Pirate Speak, and more.
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