Definition of zero hour in English:

zero hour

Line breaks: zero hour

noun

  • The time at which a planned operation, typically a military one, is set to begin.
    More example sentences
    • Accompanied by your other three team members, you begin at zero hour of the Clone Wars.
    • A few minor adjustments were made to the presentation plan, and we set 3 o'clock as zero hour.
    • As zero hour approached, Spanish-language radio stations broadcast appeals for all able-bodied Cuban-Americans to help.
    Synonyms
    the appointed time, the appointed hour, the crucial moment, the vital moment, the critical moment, the moment of truth, the point/moment of decision, the Rubicon, the critical point, the crux
    informal the crunch

More definitions of zero hour

Definition of zero hour in:

Get more from Oxford Dictionaries

Subscribe to remove adverts and access premium resources

Word of the day kerf
Pronunciation: kəːf
noun
a slit made by cutting with a saw