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zero hour

noun

Definition of zero hour

1 a :the hour at which a planned military operation is scheduled to start
b :the time at which a usually significant or notable event is scheduled to take place
2 :a time when a vital decision or decisive change must be made

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Examples of zero hour in a Sentence

  1. we're at the zero hour, so someone has to make a decision

Origin and Etymology of zero hour

from its being marked by the count of zero in a countdown

zero hour Synonyms

Synonyms
boiling point, breaking point, clutch, conjuncture, crisis, crossroad (s), crunch, crunch time, Dunkirk, exigency, extremity, flash point, head, juncture, tinderbox, emergency
Related Words
contingency, possibility; climax, turning point; happening, landmark, milestone; condition, pass, situation, strait; deadlock, impasse, stalemate; corner, fix, hole, hot water, jam, last ditch, pinch, predicament, scrape, spot; eleventh hour, last minute

ZERO HOUR Defined for English Language Learners

zero hour

noun

Definition of zero hour for English Language Learners

  • : the time at which an event (such as a military attack) is scheduled to begin

Learn More about zero hour

  1. See words that rhyme with zero hour Thesaurus: All synonyms and antonyms for zero hour

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Examples: zero hour in a Sentence